My server is experiencing inconsistent CGI execution whereby CGI scripts are not always executable. When it happens, regardless what CGI scripts you run, it will only generate a blank page for your browser. This happens a few times a day. My server is running on Redhat Linux 7.3. Need help urgently!

One more thing, though I am not sure, it seems that this problem only happens right after I upgraded Zend Optimizer to v2.10. But it could be a coincidence only. I tried re-installing Zend Optimizer several times but no improvements. Please help!