Your email provider needs to support Oauth2. If you share your email provider info, someone here may be able to advise.

Thanks for your advice, David!

The information for my email provider is as follows:

Basic authentication will be discontinued on November 4th, so I need to switch to OAuth2 authentication.

Email provider name: "Yahoo! Mail", supported by Yahoo! Japan Server Type: pop3 Incoming server: pop.mail.yahoo.co.jp Port No.: 995 Security settings: SSL/TLS

Outgoing server: smtp.mail.yahoo.co.jp Port No.: 465 Security settings: SSL/TLS

Is there any other information you need?

Do you get an error when you click the 'authentication' setting for the server? Doing that should be sufficient.

It's possible to force OAuth2 if it isn't an option in the menus, but I think your account will work with the 'generic' Yahoo servers imap.mail.yahoo.com, pop.mail.yahoo.com and smtp.mail.yahoo.com, all of which are OAuth2-supported in TB.

I have the same issue, but I'm using version 140.3.0esr. There is no option for Oauth2. When Thunderbird attempts to connect to Yahoo it fails suggesting I enter a new password. It's the same password I'm using to login to Yahoo mail from the web.

The server is imap.mail.att.net port 993 Connection security is SSL/TLS Authentication method is Normal password

Getting guidance from AT&T is impossible.

Previously I was able to do this, but had to install a newer version of Thunderbird after my Fedora upgrade failed and I had to start from scratch. Currently running Fedora 42.

I hope someone can help!

I have the same issue, but I'm using version 140.3.0esr. There is no option for Oauth2. When Thunderbird attempts to connect to Yahoo it fails suggesting I enter a new password. It's the same password I'm using to login to Yahoo mail from the web. The server is imap.mail.att.net port 993 Connection security is SSL/TLS Authentication method is Normal password Getting guidance from AT&T is impossible. Previously I was able to do this, but had to install a newer version of Thunderbird after my Fedora upgrade failed and I had to start from scratch. Currently running Fedora 42. I hope someone can help!

TB is currently developing OAuth2 support for AT&T, but in the meantime generate a secure mail key and use that in TB with 'normal password' authentication.

https://www.att.com/support/article/dsl-high-speed/KM1010523/

Thank you for your reply.

Sadly, this doesn't work--at least for me. When I get to my profile page, it only allows me to change basic things, like my name. If I click the Security icon near the top, it takes me to a page that provides for two-factor authentication, but not secure key generation.

If anyone has actually gotten this to work, please let me know the secret! :-)

Thanks, Paul

Is your process for the key the same as mentioned here?

https://www.att.com/support/article/email-support/KM1240308/

When I go to the link: https://www.att.com/support/article/email-support/KM1240308/ it lists the process for obtaining the secure mail key.

Step 1 instructs the user to go to myAT&T Profile and provides a clickable link (I went there) Step 2 says to scroll to My Linked Accounts which does not exist on that page. No way to select the email account that needs the key

My quest ends with step 2.

Kinda frustrating.

Hopefully the TB dev team will implement Oauth2 for AT&T and the issue will be solved.

Cheers, Paul

As of this morning (12/4/2025), TB is able to set up credentials for Yahoo. TB 145.0 did it!

Thanks, TB!!

I spoke (typed?) too soon.

I successfully get email messages. Awesome!!

Attempting to send emails yields the following: Login to server outbound.att.net with username blahblah@sbcglobal.net failed.

Entering the password doesn't help. Canceling the send provides this error message:

Sending of the message failed. Unable to authenticate to Outgoing server (SMTP) . Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)'.

With Oauth2 there is no SMTP that I can see.

Any clues?

Thanks, Paul

Do you have this for the outgoing:

outbound.att.net, 465, SSL/TLS, normal password, email address

where the 'password' is the same secure mail key that is used for the incoming server.

Sorry I just went back and saw this latest response.

My Server Settings for this account do not have inbound and outbound settings. It's a IMAP server with the following details:

Server Name: imap.mail.att.net Port 993 Connection security: SSL/TLS Authentication method: OAuth2

I'm able to read messages sent to this account. Attempting to send email says I need to enter my password for my account on outbound.att.net. When the password is entered it fails to login to the server. (And now the Write dialog freezes and I have to kill TB manually. Curiouser and curiouser.)

If the account is IMAP, the correct outgoing server is smtp.mail.att.net, 465, SSL/TLS, OAuth2, email address.

https://www.att.com/support/article/dsl-high-speed/KM1010523/

Silly me. I was looking under server settings for this account. All the way at the bottom of the email account tree is "Outgoing Server". I changed the Authentication method for AT&T and now it's all OK.

I never spotted the Outgoing Server section, or, if I did, didn't associate it with my emal account part of the tree.

Thank you for continuing to point me in the righ direction!

Cheers, Paul