Failed Ajax request or invalid JSON when open PKP PN plugin

OJS 3.2.1.3
PHP 7.4.15

Hello

Every time when I try open PKP PN have this error:

[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] PHP Fatal error: Uncaught Error: Call to undefined method Application::getHttpClient() in /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/plugins/generic/pln/PLNPlugin.inc.php:565, referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] Stack trace:, referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #0 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/plugins/generic/pln/PLNPlugin.inc.php(454): PLNPlugin->curlGet(‘http://pkp-pln…’, Array), referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #1 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/plugins/generic/pln/classes/form/PLNSettingsForm.inc.php(39): PLNPlugin->getServiceDocument(1), referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #2 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/plugins/generic/pln/PLNPlugin.inc.php(343): PLNSettingsForm->initData(), referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #3 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/lib/pkp/classes/controllers/grid/plugins/PluginGridHandler.inc.php(234): PLNPlugin->manage(Array, Object(Request)), referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #4 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/lib/pkp/classes/core/PKPRouter.inc.php(391): PluginGridHandler->manage(Array, Object(Request)), referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website
[Fri Feb 19 19:57:59 2021] [error] [client 46.30.164.252] #5 /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/lib/pkp/classes/core/PKPComponentRouter.inc.php(257): PKPRouter->_authorizeInitializeAndCallRequest(Array, O in /var/www/dpnlab/data/www/jrnls.ivet.edu.ua/plugins/generic/pln/PLNPlugin.inc.php on line 565, referer: https://jrnls.ivet.edu.ua/index.php/1/management/settings/website

Any ideas why it happens?
And how to solve it.
Thx )

Hi @Oleksandr_Radkevych,

I’d suggest reviewing some of the other tposts on the forum related to that message – there’s some good advice there. For example see here:

Or, try searching for “Failed Ajax request or invalid JSON PKP PN plugin” and you’ll see some relevant results.

Regards,

Roger
PKP Team

Hi @Oleksandr_Radkevych,

I think you’ve installed a version of the plugin that’s not compatible with your release of OJS. Make sure to use the Plugin Gallery to install the correct version.

Regards,
Alec Smecher
Public Knowledge Project Team