Error Access Denied: Possible Csrf Attack


after increasing the file upload limit for install a theme, we got this message;

Error access Denied: Possible Csrf Attack.

Then we dropped it again. the problem is not solved.

After making csfr false, we started getting other errors and my other sites in the same server started to give errors.

for example; i got this message from login screen when we false for csfr

It is not allowed to upload files with size more than 10MB

we checked alot of documentation and post but we couldn't find a solution. Ccs cart should be share the complete and exact solution for this. But I see no one is interested.

Could pls gety a exact solution or documentation for this issue