Today, I have received an error saying “Webresource content is too big” when I was importing PCF solution to one of our instances.
The fix is simple, the solution size which I was importing was more than 5 MB and the max file size limit for attachments was 5,120 (5 MB) in the instance. Updating the value to 10 MB (10,240) fixed the issue.
Settings –> Administration –>System Settings–> Email tab
Hope this helps.