Once again, I would like to start with thanks to the developers for untiring efforts on OJS.
There are similar titles related to task errors, and I examined them. Unfortunately, their comments did not help me. Origin of their error messages and their problem seems to be different.
I have site manager and editor roles and have full database and ftp access.
I upgraded the journal's system from OJS 18.104.22.168 to 3.0.2. Although it did not previously exist (for a few weeks), I started to get an error message when I log in as another editor. The error message is:
Failed to load resource: the server responded with a status of 500 (Internal Server Error).
Safari inspector shows that error too;
I noticed that this error occurs immediately when I open the backend control panel and repeats every time.
Although Tasks button show number of existing tasks, it does not show anything except "loading" text and a rotating circle. In the meantime, I got the following error in php log.
PHP Warning: assert(): Assertion failed in .../lib/pkp/controllers/grid/notifications/NotificationsGridCellProvider.inc.php on line 122
PHP Fatal error: Call to a member function getAssocType() on null in .../lib/pkp/controllers/grid/notifications/NotificationsGridCellProvider.inc.php on line 123
The same user (editor) also reports the same issue when he logs in with his username and password. I get the same issue when I log in as some other users (authors) also.
Hope, we can find a solution for this.
Server Environment: Linux OS, PHP version 5.6.29, Apache 2.2, database driver mysql, Database server version 5.6.34.