There was a problem signing in to plex

I just did a fresh install of v0.9.16.6 on my ReadyNAS Ultra 2 plus which I still happened to have. But whenever I go to sign in under the server - General tab I get the “There was a problem signing in to plex” error. I have double checked the settings on my router and they are correct. Was the ability to use my plex pass also eliminated? Any ideas?