What would cause an HTTP 500 internal server error when trying to log into Netwrok eManager?

The end user trying this got this error as soon as he clicked "Connect". This was working a few weeks aga after I installed it so I am confused as to what would cause this error.

check out this post on toshiba fyi "You might have an issue with IIS. See if the default Web Service is running by typing this in IE address https://localhost/. If you still get page can't be displayed try re-installing IIS."

Thanks - I will try that.