Madden 21 "Community Files Not Working" is a rather annoying error message.
An error when trying to download the Madden 21 community files has been a pretty common one. There is no one fix for this, but you can try various different thing to try to fix the problem.
Madden 21 Community Files Not Working: How to Fix
The first thing to try is to clear your cache. This can be the root of your problem, and clearing it is common for fixing problems like this.
If you are still receiving an error message, your next step should be to see when the roster was created. If the roster is too old or outdated Madden may have removed it, which is why you cannot download it. Try clearing your cache again and looking for a newer roster.
These fixes can be hit or miss, but they should work., If you still have problems, reach out to EA Sports directly about the issue.