Forum Internal Server Error when sending PM

[محروم.كوم]

Hi everyone. My forum is having trouble sending PMs. When the 'send' button is clicked after typing out a PM, it stalls, it just sits there. Then after up to a minute or two of this a page showing the following error comes up.

Quote:
Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.


Sometimes the PM is sent anyway (often times leading to multiple, duplicate PMs because the member doesn't know that it was actually sent), but more times than not, the PM doesn't send. And sometimes, though rarely, the PM sends without issue.

This started several months ago when I upgraded to v4.2 from v 3.8.

Any ideas on what's going on here? __DEFINE_LIKE_SHARE__