It is gone. There are multiple threads regarding the old site being shut down, and the fact that Bioware no longer supports NWN.
They left a message over 2 months ago, that they MIGHT restore the master server, but it seems that they are taking a very long time with that.
You can attempt to email Atari, as they are the only ones that can/might help you now. Bioware is not responding to help requests, and EA, Bioware's new owners, do not recognize NWN as being their responsibility.
We are indeed fortunate that they have so far elected to allow these forums to remain active.