Windows 10 will reach 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

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

SMTP server suddenly unreachable

  • 1 reply
  • 2 have this problem
  • 8 views
  • Last reply by Matt

krage111
krage111
more options

For a few year thunderbird works fine. Since today I can't send any mail. I got the following message:

ErrorMessage: Sending of the message failed. The message could not be sent using Outgoing server (SMTP) securesmtp.t-online.de for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again..

I check the settings, all fine. I test the settings with Outlook and it works. I use Thunderbird 38.6.0 unter Windows 10 on two computers. Since today both have the same problem.

SMTP-Server: securesmpt.t-online.de; Port 465 with SSL/TLS 

receiving mails works fine.
For a few year thunderbird works fine. Since today I can't send any mail. I got the following message: ErrorMessage: Sending of the message failed. The message could not be sent using Outgoing server (SMTP) securesmtp.t-online.de for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again.. I check the settings, all fine. I test the settings with Outlook and it works. I use Thunderbird 38.6.0 unter Windows 10 on two computers. Since today both have the same problem. SMTP-Server: securesmpt.t-online.de; Port 465 with SSL/TLS receiving mails works fine.

All Replies (1)

Matt
Matt
  • Top 10 Contributor
  • Moderator
more options

Have you contacted your provider to see if they have an issue today?