Viewing the source at the URL you posted above, I see a PHP error message:
ojs2 has produced an error
Message: WARNING: ob_start(): output handler 'ob_gzhandler' conflicts with 'zlib output compression'
In file: /var/www/html/ojs/lib/pkp/classes/oai/OAI.inc.php
At line: 61
Stacktrace:
Server info:
OS: Linux
PHP Version: 5.5.9-1ubuntu4.21
Apache Version: N/A
DB Driver: mysql
DB server version: 5.5.54-0ubuntu0.14.04.1<br/>
NOTICE: ob_start(): failed to create buffer (/var/www/html/ojs/lib/pkp/classes/oai/OAI.inc.php:61)
One work-around may be to disable compression in OAI responses. To do that, remove/comment the following line in lib/pkp/classes/oai/OAI.inc.php:
ob_start('ob_gzhandler');
Note that I’ve never heard of this before, and that code has been stable for many years, so I suspect a platform issue such as a non-standard PHP configuration or a buggy version of PHP.
Regards,
Alec Smecher
Public Knowledge Project Team