- Log out from all Gmail accounts.
- Log into the Gmail account you want to use MailTrack with.
- If you're currently using MailTrack, on your Chrome, go to https://mailtrack.io/logout.
- Then, go to mailtrack.io, click on the green button that you see in the top right corner and click "Sign in". Finally, authorize MailTrack to work at the email account that you want.
Repeat this operation with all the Gmail accounts that you want. And remember that MailTrack will only work on the Gmail accounts to which you gave permissions.