I have been having issues off and on that is pretty much making the game unplayable for a few hours to an entire day.
This started a couple days ago when I was in Act 1.
I would load into the game in Online mode and I would go to a waypoint and then begin exploring the area and after a few mins of exploring the game would load out to the main menu but I would be in Offline mode.
It did this to me about 9 times until I was able to group with someone. I loaded into their game and I was able to play the rest of the night.

Now today I just started Act 2 and I am running into the same exact issue about 2-3 mins into exploring the beginning of act 2 the game is auto loading out to offline mode.

I actually was able to make a video of this happening if any of the Dev's check this out: https://youtu.be/iojJkk3hcMw