Is there a way to check? (I tried 'downdetector') Is each Rockstar title handled independently? If they're doing server maintenance on V, then would IV be down also? I keep trying to join multiplayer games of BDB, HMN, or DB and is just says:
"Disconnected from game session. Returning to single player."
(I'm on PS3, EST - currently 7:47pm)
EDIT: ... and just like that I feel like a complete moron for not troubleshooting the problem before making a post. I restarted my PS3 and now it works. Sorry.