"Resolution not supported" message? PS4

I'm getting a "Resolution not supported" Message on my tv when I try to play my Ps4.
It was working fine before today. I've been playing Fallout 4 with the same ps4 / tv / hdmi for the past month. I unplugged my Ps4 Hmdi and power cod yesterday for the first time since getting the Ps4, to take it to my friends house and play it there. (I unplugged it while it was in rest mode).
I never used it at my fiends house, and today when I plugged it back in I got this message. 
Why has it worked perfectly until now?
I've tried unplugging and replugging the hdmi, reset the tv to factory settings, turned on the ps4 in safe mode (which I could not use because the tv still would not display anything from the ps4). Nothing seems to be working.
My tv is a Vizio 720p smart tv.