Receiving a server error with Recent Global Posts

I just tried testing the Recent Global Posts plugin and I am receiving the following server error when I use the testing URL:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, OSS2014@OSS2014 and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Thank you.