What to do When Mozilla Thunderbird Won’t Send Email?

Thunderbird is a popular email client produced by Mozilla for sending and receiving emails. Often a user is able to receive an email in the Inbox folder of the email client. But when they write, add recipients and click Send, Mozilla Thunderbird won’t send email. There is often an error message that pops up showing Thunderbird cannot send email with attachments. This sends a user in disarray as Thunderbird won’t perform any activity and restarting won’t help. Here are the steps to fix this situation on a Window, Mac or LINUX computers.

Methods to Fix Error: Mozilla Thunderbird Won’t / Cannot Send Email

Following are some of the ways through which one can restart sending emails successfully in Mozilla Thunderbird:

Solution 1 : Check the SMTP Settings

• First, launch the Thunderbird application to remove Thunderbird email problems sending when Thunderbird inbox is full.
• Then, go to Tools>>Account Settings.
• Or, click on the three bars on the top-right hand side and go to Options>> Account Settings.
• From the Account Settings dialogue box, select Outgoing Server(SMTP).Then, check to make sure that the SMTP settings are correct for the email account configured.

• Next, click on Edit button to change SMTP details and remove Thunderbird email problems.
• Also, go to the email provider’s website and search for Mail Settings>>SMTP.
• Then, verify that the Thunderbird settings match the documented settings

Solution 2 : Verify that the Correct SMTP Setting is Being Used

• Again, launch the Thunderbird application to fix Thunderbird won’t send email.
• Then, go to Tools>>Account Settings.
• Or, click on the three bars on the top-right hand side and go to Options>> Account Settings.
• From the Account Settings dialogue box, select the account name having Thunderbird email problems sending.

• Next, verify that the correct SMTP server is being used for the email address.
• For example, email cannot be sent via [email protected] through Yahoo SMTP.

Solution 3 : Make Sure that there is Nothing Blocking Emails

• First, try to send an email after switching off any antivirus or firewall software.
• This will remove any third-party software as a reason for Thunderbird email sending problems.
• Also, many ISPs block outgoing email from port 25. Change the port number to 465 or 587 after consulting the service provider.

Solution 4 : Delete Password on SMTP

• First, try to update Thunderbird to the latest version.
• Then, send an email to verify that the Thunderbird email problems sending still persists.
• If it does, go to the three bars and select Tools>>Options.

• From the Options dialogue box, go to Security>>Password.

• Then, delete the SMTP password and reconfigure email account to try sending emails again which will help you to resolve error Mozilla Thunderbird won’t send email to certain extent.

Solution 5 : Reset SMTP Password

• First, go to the ISP site, and click on Reset password.
• Change the password and add it to Thunderbird. This should remove error : Thunderbird cannot send email

Solution 6 : Raise A Support Request

• If all else fails, raise a service request with the team of Mozilla Thunderbird.
• Affix the screen-shot of SMTP settings, along with email ID, Mail provider(eg Gmail), ISP etc.
• Also, include the version of the firewall and antivirus being used.
• Make sure to mention the Thunderbird version number and the operating system details.
• Now, this should be able to remove Mozilla Thunderbird problems sending emails.

Limitations of Manual Process

• Technical Assistance Required: In every second step help from ISP provider is needed.
• Confusing Steps: There are too many steps that could confuse a home user or a non-technical person.
• Not a Guaranteed Resolution: The manual solution may or may not be able to fix the Thunderbird email sending problems when Thunderbird mailbox size exceeded.
• Risky Task: This is email configuration and changing settings which is a risky undertaking. It must be implemented with a complete understanding of email settings in Mozilla Thunderbird.

Solution 7 :  Use Alternative Solution

Often the manual solutions are unable to resolve the Thunderbird cannot send email or Thunderbird won’t send email issue. In such a case, many switches from Thunderbird to other email applications. There is a third-party tool that can directly perform this task without any data loss.  Just upload the Thunderbird email folder directory to the tool and will migrate each .mbox to a new .pst file.

Conclusion

SMTP issues can arise at any time and affect the daily working of a user. It is important to rectify this issue and overcome the Thunderbird won’t send email problem. Many solutions have been described in this post to resolve the situation. If the issue persists then, there is no option but to switch email client. One can move from Thunderbird using the Software described in this post.