Windows 10 reached EOS (end of support) on October 14, 2025. For more information, 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

Thunderbird Cannot Send Email

  • 1 reply
  • 0 have this problem
  • Last reply by sfhowes

nstarr
nstarr
more options

I can receive, but not send, emails using Thunderbird on my PC. I believe this problem began when Thunderbird was updated on 1/13/26. I have no problems sending email on my tablet.

My service provide does not support TLS 1.2, so I tried changing security.tls.version.min to 1. This did not help.

The attached shows the error message and my SMTP settings (1st image) and my service provider's email server settings. I tried changing the SMTP port to 587, but this resulted in a time out error.

Any help is appreciated, Norm

I can receive, but not send, emails using Thunderbird on my PC. I believe this problem began when Thunderbird was updated on 1/13/26. I have no problems sending email on my tablet. My service provide does not support TLS 1.2, so I tried changing security.tls.version.min to 1. This did not help. The attached shows the error message and my SMTP settings (1st image) and my service provider's email server settings. I tried changing the SMTP port to 587, but this resulted in a time out error. Any help is appreciated, Norm
Attached screenshots

All Replies (1)

sfhowes
sfhowes
  • Top 25 Contributor
more options

They recommend port 587 for the outgoing, but don't state if the security is STARTTLS or None. If it's None, the authentication would be 'password, transmitted insecurely'. Also, the User Name might be the full address instead of just the part before @.

A timeout can also be caused by AV scanning of outgoing mail. To test, temporarily remove (not disable) the AV, unless it's Windows Security.

Ask a question

You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.