Problem with Remote Access in server 2008

[sparker]

My windows VPN has worked perfectly well for years and has been running fine since April last year on VM'd Ws2K8R2 servers but has now suddenly decided to stop.

I have tried deleting and reinstalling and have tried it on other (virtualised) servers all to no avail. I just get the following error: The remote connection was denied because the user name and password combination you provided is not recognized, or the selected authentication protocol is not permitted on the remote access server. Needless to say I am using all standard settings but still have no joy - anyone know of any likely culprits or a way to get more info on this issue or failing that some free vpn servive that might get me going again?

Many thanks