Cannot Send Messages

If you cannot send messages, this page provides a series of steps you can use to check for common problems.

Verify your SMTP outgoing email settings

  • Select Tools|Account Settings... and then Outgoing Server (SMTP) from the bottom of the list on the left side of the panel. Check that the settings are the same as documented on the mail settings article for your mail provider on (Gmail, Yahoo, Comcast, Hotmail, Sympatico) OR
  • If there is no article with your specific mail provider's mail settings then look for an SMTP mail settings article on the mail provider's site. This is usually in the support section of their website; searching for "mail settings" or "SMTP" will usually find it. Check that your Thunderbird settings match the documented settings.


Verify the correct SMTP Server is being used

  • Select Tools|Account Settings... Verify that you are using the right SMTP server for the email address. Most of the time you cannot send messages from one account provider using another account provider's service. For example, you cannot send a mail from "" through Yahoo's SMTP server.


Verify that your outgoing email is not being blocked

Verify that your outgoing email is not being blocked by your firewall, antivirus software or your Internet Service Provider:

  • Try briefly turning both antivirus and firewall off, sending a test email and turning them on and sending another test email.
  • Many ISPs block outgoing email on port 25. You may have to switch to another port (e.g. 587 or 465). Contact your ISP's support to see if they are blocking your outgoing email port.

Delete SMTP Password

Try deleting your SMTP password.

Reset SMTP Password

Try changing your SMTP password. This is usually done via a 'reset email password' form on your ISP's support website.

If this list doesn't help

Please create a new support request with a screenshot of your SMTP settings with your userid obscured and include the following information: your mail provider (for example, Gmail), ISP (for example, Comcast), firewall version (if any), antivirus software and version (if any), operating system and version (for example Windows 7 or Mac OS X Mavericks), Thunderbird version (for example Thunderbird 38.2.0). See the How do I create a screenshot of my problem? article for information on how to create a screenshot.

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