I had a problem with these symptoms two weeks ago, when I tried to use my ATV3 in wi-fi mode. I've bought a pair of powerline adapters (av500) and solved my problem.
Thanks for the tip, but the ATV is already connected with ethernet cable.
Also tried downloading a new copy of PlexConnect, reusing the old certificate and changing the Settings to point it to my PMS manually, still same error.
You don't seem to be logged into myPlex... Do you have "RequireAuthentication" or PlexHome active on PMS side?
It wont sign into MyPlex on the ATV, the loading wheel just stays and spins when I try to login.
Yes, I did enable PlexHome, but I tried to remove the extra user and enable DLNA again, but still didnt work. Also I dont have "Require authentication on local networks" turned on.
I also verified that "Require authentication on local networks" Is deselected in the "Settings->Connect" area, also tried toogling it on/off without any success.
Tried logging into Myplex on the ATV, both with username and email address. leaved it loading for a while but it didn't sign in.
Any ideas what to do next would be highly appreciated.