I’ve just tried to visit that web site and it looks the web server is slow to respond and when it does respond eventually sends a 500 Internal Server Error
response.
$ curl -I https://www.wikipetro.org/
HTTP/1.1 500 Internal Server Error
Date: Sun, 11 Mar 2012 19:13:04 GMT
Server: Apache
X-Powered-By: PHP/5.3.10
Expires: Wed, 11 Jan 1984 05:00:00 GMT
Last-Modified: Sun, 11 Mar 2012 19:13:05 GMT
Cache-Control: no-cache, must-revalidate, max-age=0
Pragma: no-cache
Connection: close
Content-Type: text/html; charset=utf-8
Try the usual troubleshooting steps.
Have you tried:
– deactivating all plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s).
– switching to the Twenty Eleven theme to rule out any theme-specific problems.
– resetting the plugins folder by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems.
– re-uploading the wp-admin and wp-includes folders from a fresh download of WordPress.