If you are having difficulty in setting up the Email Sync Plugin using your main email password, then you we recommend using the App Password instead. This should then solve the issue you are experiencing.
The help articles below show how to find the App Password for your emails:
https://support.google.com/mail/answer/185833?hl=en-GB
https://support.microsoft.com/en-us/account-billing/using-app-passwords-with-apps-that-don-t-support-two-step-verification-5896ed9b-4263-e681-128a-a6f2979a7944