For those who are having issues still, I'd suggest looking in your PHP logs. I had my site go down out of the blue after no changes on the server. Web Server logs showed only timeouts. Head to the PHP error log and found 100's of these:
Code: Select all
PHP Warning: PHP Startup: Invalid library (appears to be a Zend Extension, try loading using zend_extension=php_opcache.dll from php.ini) in Unknown on line 0
In addition to this, there were 20 PHP/CGI processes going.
Once I disabled the extention and killed the rogue processes, Joomla came back.
Hope it helps.