XF 1.3 Forum repeatedly crashes - shows "no data received"

[Elvo00000]

Every now and then when a user tries to post, the post doesn't go through, and then when they refresh the forum it shows this:

That's for Chrome obviously but it happens in Firefox and other browsers as well. Happens when a user tries to post, not when they're just reading the forum. The forum crashes (but only for the user trying to post) for around 30 or so seconds and then back to normal.

Most of my users are reporting this problem.

 

[Paul B]

This is typically due to PHP crashing.
It could be due to incorrect libraries or some other reason.

There may be some server error logs which may help to identify the cause, but ultimately this is an issue you need to highlight to your host and ask them to investigate and resolve.