Error 500 - Internal Server Error

[fossxplorer]

I often get this for the some web sites:

Error 500 - Internal Server Error
A generic error message, given when no more specific message is suitable

Log shows:
Handler for fastcgi-script returned invalid result code 1
[Sun Sep 27 21:40:34 2015] [error] [client ] (104)Connection reset by peer: FastCGI: comm with server "/home/client1//client1.com.0fake" aborted: read failed


sh /script/fixweb --client=clientname fixes it but clients are complaning.
What's the problem?
 

[MRatWork]

What's you mean 'but clients are complaning'?.

[fossxplorer]

The customers don't like their website being down often with error 500

But i read that it might be related to opcache. I use opcache with php54, perhaps should update to php56?

What's you mean 'but clients are complaning'?.

[MRatWork]

Try using apc/apcu instead opcache.