gmail not working
A couple weeks ago Gmail suddenly stopped working for me in Mail 11.5 on MacOS High Sierra 10.13.6.
I keep getting an error message see attached pic
i tried a different mail client, see attached pic
i tried deleting my security certificates, and that didnt work so i restored them from time machine backup. I've tried changing the default browser and deleted one of my gmail accounts but i cant add it back in. I can log in just fine through the mail app because i get alerts from Google on my phone that someone logged in. But no mail. I can log into Gmail on my browser too. Any help would be appreciated thanks.
Mac mini, macOS 10.13