I've also been having this problem and I just disconnect without even really doing anything other than standing around. This started on June 4th around 7pm EDT, but hours before that I was logged in just fine without any problems at all. Tried resetting modem and router, wireless, wired connection and nothing changed. I tried again the morning of June 5th and still getting the same issue.

I saw that usually this happens when it's my connection that is an issue, but it's not the case because any of my other games, streaming video, and connection to PSN would have a problem too and they do not.

This problem is occurring on PS4 for me.