So I've had my Nest thermostat since 2021 recently our AC started coming on and then shutting off after like a minute and then coming on again. But not the heater, only the AC. I tried to switch it back to our old thermostat (we rent so we had to save it) to see if it would still happen but the person who installed it didn't take a picture of the wiring on the old one so I couldn't get it to work. There's a Red (R) Blue (Y1) Green (unlabeled) and a whiteish Wire also unlabeled.
When I took my Nest thermostat off I took a picture (Attached) but the old thermostat didn't match up with those assignments. And didn't turn on.
So I went to put the Google one back on and put it back together exactly the same but now it won't work, is says no power and I keep getting Error E298.
I had the breaker off while I did all this. Google keeps saying it's because I don't have a C wire but I havent had one in the years our thermostat has functioned just fine.
Help?