Ubisoft has deactivated the multiplayer features of Watch Dogs 2 to prevent players games from crashing during the single player experience. Ubisoft released a full statement on the move, and how they are working to resolve it...

During the pre-launch phase of Watch Dogs 2, we discovered an issue tied to the seamless multiplayer feature that caused the game to lag and crash periodically. In order to eliminate that issue at launch and for players to enjoy a smooth game play experience, we have decided to wait to launch the seamless multiplayer feature until the patch that fixes this issue is deployed. The patch is currently in certification by Sony and Xbox.
In the meantime, players can still play the full single-player experience without any concerns and play co-op by inviting friends through the game menu. But that does mean that the Bounty-Hunter mode and other activities that would occur with other outside players who enter your game will be unavailable until the patch is deployed on each platform.
To follow updates on Watch Dogs 2 and follow the status of the seamless multiplayer, please feel free to visit our Watch Dogs 2 Community site.

No word on how long the patch will hang out in certification, but it sounds like some parts of the game can still be enjoyed. Personally, I would wait for the patch to purchase given how much of a mess The Division was, but I'm not you. Let's hope this patch fixes the issues and doesn't create new ones.