How to Fix Thunderbird SMTP Error With Ease?

Rollins Duke   
Published: May 9th, 2024 • 3 Min Read


While working on Mozilla Thunderbird, users are able to receive their emails but unable to send that mail, it prompts an error message saying ‘Try again.’ It is Thunderbird SMTP Server Error- Messages cannot send.

Cause behind Error

If a user is unable to send any mail via Mozilla Thunderbird then, it is just due to SMTP server error.  SMTP server manages the whole email delivery process. An error comes up due to as the ISP blocks the outgoing ports as a guard against the connections, which are utilized to spend spam.  This error can occur with various statements.

Solution to Remove Thunderbird SMTP Error

Method 1: Check Mail Outing Settings

Main cause of Messages Cannot Send error is due to disturbed SMTP settings. Therefore, it is important to inspect outgoing server settings as mentioned:

  • Open Mozilla Thunderbird in your machine >> click on the Tools tab
  • Choose an option of Account Settings  from menu list
  • Click on the option of Outgoing Server (SMTP)
  • Now, check SMTP server settings are accurate for configured email mailbox or not
  • Make sure that email provider’s site and seek for the Mail Settings >> SMTP

Once it is done then, check the correct SMTP setting is updated or not by following the given steps:

  • Open the Thunderbird and click on option of Tools
  • Choose Account Settings >> select account name that has issue
  • Make sure that correct SMTP server is being used or not of the email address

Method 2: Check for Blocking Services

Most of the time, antivirus and firewall application blocks the pouting messages of Thunderbird. Therefore, it is important to check it:

  • Try to send mail without disabling any of the antivirus or even firewall software. Then, send an email after disabling it.
  • Moreover, numerous of ISPs block outgoing mails from port 25. Therefore, change port number 465 or 587 after consulting service provider.

Method 3: Delete SMTP Password    

An email sending problem can be solved by deleting and reconfiguring Thunderbird email account. :

  • Update Thunderbird email client to the latest edition
  • Once it is done, try to send mail for checking the issue still persists or not
  • If it is then, choose Tools >> click on Options
  • From the Options wizard, choose on Security >> click on Password
  • Now, delete SMTP password and configure account again. After that, try to send mail again and this can help to resolve Thunderbird email not sending problem.

Once the mail is send then, you can reset your SMTP password if you want to be secured.

Final words

SMTP problem can occur anytime and on any email client. Similar as in case of Mozilla Thunderbird, which pop-ups “Thunderbird SMTP Error – Messages Cannot Send.” Therefore, we have suggested all the common fixes to remove this error message.