Thunderbird: The Message Could Not Be Sent Because The Connection To Outgoing Server (SMTP)

 

Sometimes, the wrong SMTP is selected in your settings. A wrong SMTP server cannot send mails from your Thunderbird email ID. In order to fix this issue, you need to select the correct SMTP server in your settings.

Thunderbird The Message Could Not Be Sent Because The Connection To Outgoing Server (SMTP)

Inspect if the proper settings are in use or not –

• Open Thunderbird on your computer.
• Go to the Tools option.
• In Account Settings, select the account name which is having the sending email problem.
• Make sure whether the proper SMTP server is in use or not for the respective email address.

E.g. – an email address such as abc@gmail.com cannot send emails through a Yahoo SMTP.

Check these settings and reset if there is a problem with the settings. Now try to send an email to check whether the problem is solved or not.

Thunderbird Won’T Send Email With Attachment

If the solutions mentioned above are not working for you, then check if anything is blocking the emails or not.

Follow the steps the get rid of this annoying issue.

• Switch off your antivirus and firewall program and try to send an email again to check if it is blocking the emails or not.
• This will remove the third-party software reasons which might cause this sending email issue.
• Some ISPs block the outgoing emails which are sent from port 25. In that case, you have to change the port number to 465 or 587.
• Do consult with your Internet Service Provider Customer Care Service in order to know the exact port number you need to put in the port number dialog box.

Another reason for this problem could be that your attachments exceed the maximum file size. You cannot send an email with attachments if the attachment size exceeds the maximum size.

This limit is set by the email service providers and may vary for every service provider. Check the Thunderbird maximum email attachment size and try to send the mail again.