Gmail Manager NG 0.6.5.2 keeps asking for password Bewertet mit 5 von 5 Sternen

I have multiple gmail accounts. The password is correct as I successfully logged in using another browser like Internet Explorer. FireFox was working fine until 2 days ago 2 of my accounts keeps asking for password and earlier this morning today, all accounts are asking for passwords, including the account with 2 steps verifications. Please advise.

Thanks,
Mike