Last week, I moved the wordpress instance to new server. After that I frequently get 500 Internal Server Error. This error comes all of the sudden. The apache error log does not contain any fatal error messages but it contains PHP warning messages.
Whenever this error occurs, I restart the apache and the site is back to normal state. What may be the reason for this 500 Internal Server Error?
How does restarting apache solves this error? Only this site gets this error, other sites deployed to this server are working fine.