Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Thunderbird can receive email but not send email

  • 1 reply
  • 1 has this problem
  • 193 views
  • Last reply by sfhowes
  • Archived

Susan Beecher
Susan Beecher

My Thunderbird email (att email) can receive emails but not send them. I get an error message that says "Login to server with [username] failed". Then "Unable to authenticate to Outgoing SMTP server. Check password and authentication method." So in order to use ATT's email with Thunderbird, I recently changed the authentication method to Oauth2. The authentication method for the outgoing server is "Normal password". The other possible settings are Encrypted password, Kerberos and NTLM. Should I be using one of those?

This worked just fine until today. I am puzzled.

My Thunderbird email (att email) can receive emails but not send them. I get an error message that says "Login to server with [username] failed". Then "Unable to authenticate to Outgoing SMTP server. Check password and authentication method." So in order to use ATT's email with Thunderbird, I recently changed the authentication method to Oauth2. The authentication method for the outgoing server is "Normal password". The other possible settings are Encrypted password, Kerberos and NTLM. Should I be using one of those? This worked just fine until today. I am puzzled.

All Replies (1)

sfhowes
sfhowes
  • Top 25 Contributor

Use 'normal password' authentication for incoming and outgoing, but enter a secure mail key instead of the regular account password.

https://support.mozilla.org/en-US/questions/1330602