FCGID stops working spontaneously (mod_fcgid: error reading data from FastCGI server)

I am running a couple of (GPL) Virtualmin instances. It has happened a couple of times that websites cease to function, and generate a 500 error. Switching the Virtual servers running on that host to use mod_php works around the issue. When it happens all Virtual Servers on that host cease the work if they use php. (Static sites are OK).
Apache error log: [fcgid:warn] [pid 2261] (104)Connection reset by peer: [client x.x.x.x:54160] mod_fcgid: error reading data from FastCGI server

Up to yesterday I thought I caused this because of tinkering on the server. However yesterday it happened to one of the servers at 3h in the morning, i.e. completely spontaneously.

To date I have been unable to find the cause. I have trawled all the forums here for clues about ‘500 errors’. However nothing describes the issue I am experiencing, i.e. that a site goes from fully functional to not, without any apparent cause or change.

Transferring Virtual Servers to other hosts not affected works OK too (i.e. the sites will happily run using FCGID on another host), so I know that there’s nothing in the Virtual Server’s content that would cause this.

Not even a full restore of the server will correct the issue. The only fix I have found so far is a full rebuild from scratch.

Host CONFIG: Virtual Server (1GB RAM, 20GB HDD, 1CPU)
APACHE 2.4.6
PHP 5.4.16 or 5.6.5
All hosts managed by CLOUDMIN 9.0

Any ideas out there?

I know this is ancient history to you but I’m stuck with this same issue now and it’s (no doubt unfairly) dented my trust in Virtualmin. After installing php7 (multiple php setup) my sites randomly it seems drop out with this error. Change the php execution mode gets it running for a while only to happen again shortly after.

Did you ever find a resolution? (if you can even remember!)