Xml sitemap generator for wordpress 4.0.8 даёт ошибку. Как исправить?

Привет. Подскажите что случилось с плагином XML Sitemap Generator for WordPress 4.0.8 выдает ошибку:
Internal Server Error

The server encountered an internal error or

misconfiguration and was unable to complete

your request.

Please contact the server administrator at

webmaster@site.com to inform them of the time this error occurred,

and the actions you performed just before this error.

More information about this error may be available

in the server error log.

Additionally, a 500 Internal Server Error

error was encountered while trying to use an ErrorDocument to handle the request.