On a large Moodle site we host when you access this url :-
You get just this message :-
Choose which logs you want to see:
NO FOOTER or SELECTOR DROPDOWNS shown
Error log doesn't show any details with Debugging on All.
- Run the report on a site with data.
- Limit the memory for the report adding this line after the requires
- Should give you the limited output, if the page is giving 500 increase the memory or if it is working lower the memory.