Kinda saw this coming.
When the online component for Grand Theft Auto V launched in October, it suffered from a series of problems. Now, with the latest update delivering online Heists for the first time, Rockstar is experiencing more server problems.
Many players say they can't connect at all, while others are reporting limited connectivity. That's the current status, which you can always check here ; at the time of this article, all platforms are listed as "Limited" but Rockstar is working on the problem. The issues don't appear to be as severe or as widespread as the initial glitches associated with the launch of GTAO, but it's still frustrating.
So, if you can't form up your four-man Heist team just yet, have patience.
Related Game(s): Grand Theft Auto V