Look at the checkbox Accept cookies from sites.Do ≡ > Preferences > Privacy & Security > Web Content.How to avoid or correct an OAuth failure caused by rejected cookiesįirst, verify your general setting for cookies in Thunderbird: You need to accept cookies at least temporarily using one of the methods described below. If you have rejected cookies in Thunderbird, the OAuth setup process will fail because some cookies must be accepted to store data between page updates. Ensure that Security Settings > Authentication method is set to OAuth2.Ĭookies and javascript must be enabled for the OAuth 2.0 setup process to work.

Underneath your account entry, select the Server Settings subsection (if it is not visible, you may need to toggle the > button first).

Click on the OK button to confirm your SMTP Server settings.

In the SMTP Server dialog, ensure that Authentication method is set to OAuth2.

Click on the Edit SMTP Server… button on the right.

At the bottom of the settings pane, look for Outgoing Server (SMTP).Ensure that your Thunderbird Gmail account is set to OAuth2 Outgoing Server (SMTP) You can also use the following steps on any newer version of Thunderbird to double-check that your authentication method is actually set to OAuth2.

However, if you want to continue using an old version of Thunderbird below 91.8.0 at your own risk, you will have to change the authentication method to OAuth2 yourself. If I close out of Thunderbird and then restart it and everything works fine for another hour or two and then the problem starts again.We recommend updating to the latest version of Thunderbird for the latest security fixes and many other bug fixes and improvements. Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'. Unable to authenticate to Outgoing server (SMTP). Login to server with username failed.Īnd a request to enter a new password. If I cancel the message I get a popup with: I can still receive email from gmail and send/receive from my MS account.Įverything initially works but after a short period if I attempt to sent an email via gmail the sending dialog never completes. My problem is that after an hour or two, outgoing mail via gmail and SMTP fails to authenticate requiring me to restart Thunderbird. I have Mozilla Thuderbird 91.11.0 (64-bit) configured with a gmail account and a MS account via Owl.

Gmail server settings for thunderbird