How to Troubleshoot Thunderbird SMTP Error and Send Messages Successfully?

The Problem

Using Mozilla Thunderbird, users can receive emails, but are unable to send them, prompting an error message that says ‘Try again.’ This is Thunderbird SMTP Server Error- Messages cannot be sent.

Error Cause

Users who are unable to send mail via Mozilla Thunderbird may be experiencing SMTP server errors. An error occurs when the ISP blocks outgoing ports as a safeguard against spam connections. An SMTP server manages the entire email delivery process. Several statements can cause this error.

Thunderbird SMTP Error Solution

The first method is to check the mail outgoing settings, Method 1

This error is typically caused by disturbed SMTP settings. Therefore, it is important to inspect your outgoing server settings as follows:

• Click on the Tools tab in Mozilla Thunderbird
• From the menu list, select Account Settings
• Select Outgoing Server (SMTP)
• Check SMTP server settings for configured email mailboxes
• Visit the email provider’s site and look for Mail Settings >> SMTP

By following the steps below, you can check if the correct SMTP settings have been updated:

• Click on the Tools option in Thunderbird
• Select Account Settings >> Select the account that has the issue
• Verify that the correct SMTP server is being used for the email address

Check for blocked services using Method 2

Thunderbird’s pouting messages are often blocked by antivirus and firewall applications. Therefore, it is essential to check:

• Send an email without disabling your antivirus or firewall software, then send it after disabling it.
• Furthermore, numerous ISPs block outgoing mail from port 25. Therefore, change port number 465 or 587 after consulting your service provider.

The third method is to delete the SMTP password, Method 3

Removing and reconfiguring Thunderbird email accounts can fix email-sending problems:

• Install the latest version of the Thunderbird email client
• Send a mail once it has been completed to see if the issue still persists
• Choose Tools >> click on Options if that is the case
• Choose Security >> click Password from the Options wizard
• To resolve the Thunderbird email not sending issue, delete the SMTP password and configure the account again. Then, try sending an email again.

You can reset your SMTP password once the mail has been sent if you want to be secure.

Words of Wisdom

This problem can occur on any email client. For example, Mozilla Thunderbird shows “Thunderbird SMTP Error – Messages Cannot Send.” Therefore, we have suggested all the common fixes to get rid of this error.