"No authority could be contacted for authentication"

Hi guys Just wondering if anyone else has had this issue? My felling is that the IIS box is trying to connect to the domain controller and is failing to do so. If this is correct then technically this means it is nothing to do with our code but rather the server infrastructure, does that make sense? In terms of the actual error. It occurs randomly throughout the day and the only thing the user sees is a white screen with this text written in the top left hand corner. When it occurs it affects anyone who tries to connect to the server during the time that this error is present. It seems to last for about 30 seconds before the system comes back up again. For people who are affected when they click refresh after the 30 seconds has gone by some have their sessions terminated and others can continue as normal. If a user pressed no button during the 30 second window, afterwards they can click a but ...