Step 1 : Go in your Google settings and delete MailReach as a third party app.

The following video shows the process :

1. Go in your Google account settings
2. In the left menu, click on Security
3. Scroll down to Third-party apps with account access
4. Click on MailReach
5. Click again on MailReach
6. Click on Remove Access and confirm

Step 2 : Go back on MailReach and connect the Google account.

1. Go back on MailReach
2. Connect Account
3. Select Google Workspace / Gmail
4. Click on Sign in with Google

Well done, that should be fixed by now.

Updated on: 13/04/2022