Using older versions of Outlook for Mac for personal email and calendar
HERE IS THE SOLUTION THAT WORKED FOR ME THAT I GOT FROM MS:
We need to delete the Gmail account and re-add it back. So please follow the steps below:
- Navigate to Outlook menu bar at the top of the screen
- Click on "Tools" -- "Accounts" and click on the '-' sign towards bottom left and when prompted, click on Remove from All Devices.
- Click on the "+" sign
- Type in the email address and click on "Continue"
- Click on the "Not (Google/Yahoo/iCloud/IMAP)?" on the top right of the next window which appears
- Toggle the switch next to "Sync with Microsoft Cloud", so it turns to gray from blue
- After which, select "IMAP"
- Type in your password for the email account
- Click on "Add Account"
You can refer the link below for more information: