I can't connect either. Same error.
At first I thought it was because I already had an open log-in session on their server, due to suffering a CTD about half an hour ago.
Then I tried to visit Subsim and found that Neal had taken the forum temporarily offline. It seemed all too coincidental for a while... the word 'conspiracy' came to mind!
If only there was DRM in the war - Germany wouldn't have even got as far as invading Poland...