MyBB Community Forums

 ..... is currently unable to handle this request.
HTTP ERROR 500

I upgraded from 1.8.6  to 1.8.10, but now forum doesn't load. I did forget to chmod, so I started everything again and chmoded, upload all files again, but same problem. Now I reverted the db and uploaded the old index.php forum shows. 

But when I check upgrade in the admin I always get error:  
There was a problem communicating with the version server. Please try again in a few minutes.

How can I upgrade now without problems?

Check your server error logs to see what was actually causing the issue, a 500 is a very generic error that could be solved by a lot of things.