Our new website that had been working fine for weeks is suddenly giving a blank white browser screen intermittently. Most of the time it works fine. When it happens it doesn't effect all users simultaneously. Some users can still access the site while some can't.
The problem occurs regardless of browser (IE, FF or Chrome). When it happens I notice that network activity flatlines (Windows Task Manager). It also seems to occur at certain times of the day, around 9:30 am, 3:30 and 5:30 pm for some users, others report getting it at random times. When it happens it lasts about 10 minutes and then spontaneously resolves.
We've been going back and forth with our webhost (GoDaddy) for a week now, they insist the problem must be with the website installation or config.
My partner had installed a security plugin called "Bulletproof" (we've since deleted it). He reports that it rewrote the htaccess file. But even after restoring that file to it's original state we have the problem.
We've also deactivated the WP Supercache and wordfence plugins.
All the other plugins we've used with other websites we've run without any problems.
I enabled error logging at the hosting control panel and we're collecting server errors like this:
[Thu Jan 24 15:10:34 2013] [warn] [client 18.104.22.168] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server
[Thu Jan 24 15:10:34 2013] [warn] [client 22.214.171.124] (104)Connection reset by peer: mod_fcgid: ap_pass_brigade failed in handle_request_ipc function
[Thu Jan 24 16:49:32 2013] [warn] [client 126.96.36.199] (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server
[Thu Jan 24 16:49:32 2013] [error] [client 188.8.131.52] Premature end of script headers: admin-ajax.php
The times seem to correspond to "white screen" events.
Any suggestions on how to resolve this would be greatly appreciated.