We have upgraded our from Moodle 3.7.1+ to 3.9.1
However now if you click on Add an activity or resource you just get a popup window with spinning icon and nothing is loaded.
Anyone having this? How can we resolve this problem?
We have purged all cache - did not help.
We have tried to chose different themes (Classic, Boost) - did not help.
Enabled debug messages in Moodle - did not show any error messages.
Checked apache error logs, no errors about activity chooser.
If I open Firefox inspect element > Console and the moment I click on Add an activity or resource I get this line: uncaught exception: Object