Native XML is not exporting it gives 503 Service Unavailable error

Hi
I’m using OJS 3.2.1.2
|OS platform|Linux|
|PHP version|7.4.11|
|Apache version|Apache|
|Database driver|mysqli|
|Database server version|5.7.31|

My problem is that using Native XML plugin i am trying to export the issues. but in some issues, it gives “503 Service Unavailable error”. (the interesting is that i can export articles of that issue one by one but it is not exporting the issue)

the error logs are:

[11-Feb-2021 16:57:06 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:07 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:12 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:13 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:14 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:20 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:26 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:42 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:45 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:57:51 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:03 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:07 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:09 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:15 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:22 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:27 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:38 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:40 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:45 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:46 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:46 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:47 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:53 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:58:59 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:00 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:01 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:06 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:19 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:34 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:35 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:39 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:44 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:51 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:54 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:56 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:57 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:58 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:59 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 16:59:59 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:01 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:02 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:04 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:05 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:11 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:11 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:12 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:13 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:13 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:14 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:20 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:21 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:00:21 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:01:10 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:01:43 UTC] PHP Warning:  ini_set(): A session is active. You cannot change the session module's ini settings at this time in /home1/ijcuaaaa/public_html/ijcua.com/lib/pkp/classes/session/SessionManager.inc.php on line 69
[11-Feb-2021 17:01:43 UTC] PHP Warning:  ini_set(): A session is active. You cannot change the session module's ini settings at this time in /home1/ijcuaaaa/public_html/ijcua.com/lib/pkp/classes/session/SessionManager.inc.php on line 69
[11-Feb-2021 17:01:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:02:24 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:02:33 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:02:45 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:03:09 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:05:06 UTC] ojs2: 404 Not Found
[11-Feb-2021 17:06:26 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:08:53 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:09:32 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:10:09 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:10:34 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:17 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:20 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:24 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:27 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:38 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:46 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:52 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:11:55 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:12:00 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:12:21 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:12:24 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:14:42 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:17:14 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:17:43 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:17:46 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:17:50 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:18:15 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:19:15 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112
[11-Feb-2021 17:19:17 UTC] PHP Deprecated:  Non-static method PKPApplication::getRequest() should not be called statically in /home1/ijcuaaaa/public_html/ijcua.com/plugins/generic/customHeader/CustomHeaderPlugin.inc.php on line 112

previously I opened another request but i didn’t receive an appropriate reply from your side:

It would be great to help us in this regard.
Sicnerely

Hi @ijcua,

I’ll respond to your other post; please don’t post the same content several times, as it clutters the forum.

Regards,
Alec Smecher
Public Knowledge Project Team