Starting February 15, 2021, G Suite accounts will only allow access to IMAP accounts using OAuth. Password-based access will no longer be supported by Google.

Beginning June 15th, 2020, users who try to connect via "Less Secure Apps" (LSA) for the first time will no longer be able to do so. Users who have connected to LSAs prior to this date will be able to continue using them until usage of all LSAs is turned off on February 15, 2021.

How to Convert to OAuth

Converting to OAuth is easy, and fun! 👍

1. Within Postbox, navigate to Options | Preferences > Security > Passwords > Saved Passwords and click the "Show Passwords" button.
2. Take a screenshot of your passwords, so you have them as a backup.
3. Remove all of your G Suite passwords from the Password Manager, then close the panel.
4. Navigate to Options | Preferences > Accounts. Select the first G Suite account and change Authentication to "OAuth2." Repeat this step for each of your G Suite accounts.
5. Next Navigate to Options | Preferences > Accounts > Outgoing Servers. Here you will want to edit each G Suite server and change Authentication to "OAuth2."
6. Once complete, restart Postbox, and it will authenticate with each of your G Suite accounts. Follow the onscreen prompts and you're all set!