Apache 500 error with code 732

I've developed my website and RESTful APIs. Few weeks ago everything was working fine then I found a strange error on my VPS. See the screenshot below:

500 Internal Server Error with code# 732

I'm using:

• CentOS 6.5
• Apache 2.2.x
• PHP 5.6.x with FastCGI
• Laravel 5.1

The error shows up eventually (not every time), I checked all server logs including Apache access_log.log, error_log.log and domlogs. There was no information about the error.

I also tried to find the issue with top c command and all server resources were free at the time of error. The server was at idle state.

Any help would be great.

Thanks

via Chebli Mohamed