Mac Mail App Not Opening. Inconsistent internet connections and mail service provider outages can cause mail to stop working, too. The mail app was working fine at first but now it will not open.
But do not worry, your mails will not be removed from google’s servers, you can still access your mails via gmail.com web site. I've tried countless times to fix this but nothing has worked. How to test an issue in another user account on your mac
Whenever a new version of macos is released, there are expectations that “major” bugs would be fixed.
So don't use the gmail portal to connect your gmail, but generate an app password from google website and manually set up your gmail using the normal email portal in the. The same is true of the 3 other apps as part of the pack (chat, people and calendar is it?) i've tried uninstalling and reinstalling the apps to no avail. Typically, problems with mail come down to incorrect configurations and the need to apply a recent update to the app. Then close mail and attempt to open it again via the dock.