This happens when I want to open the tab “courses” of TutorLMS.
Then it does not show any of the courses created and I cannot create a new one.
It also shows the line on the top of the page: “There has been a critical error on this website. Please check your site admin email inbox for instructions. If you continue to have problems, please try the support forums. Learn more about troubleshooting WordPress.”
And when I deactivate the plugin “Download Manager Pro” it all works OK, I can see and edit/add TutorLMS courses again.
