
Getting SMTP Server Error- Message Cannot Send in Mozilla Thunderbird and want to fix this problem immediately?. Here in the given blog post, we are going to introduce you to the best solutions for the question “How to Fix Thunderbird SMTP Error- Messages Cannot Send” to reaccess your email account in the Thunderbird application
Thunderbird is a free email application that offers various amazing features to its users without any charges. But like other application users faces different types of errors while using this application like- SMTP errors. Due to this error, the faces problem in sending/receiving messages and an error prompts again Try Again to send the messages.

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What are the causes behind this error?
SMTP server error blocks the messages and an error appears, it may happen when ISP restricts the outgoing ports from sending messages and mark it as spam. Here, we have written the manual method as well as direct methods to solve this error.
Method 1- SMTP Email Outgoing Settings
The main cause why the user is unable to send the emails it is due to disturbed SMTP setting. Therefore, it is important to check the server settings
- Open the Thunderbird application on your computer.
- Click on the Menu option then select account settings
- From the Account setting windows, click on Outgoing server tab
- Press SMTP server settings whether they are rightly configured.
- Check that email provider site and search for mail settings and SMTP
- Verify the mail settings and check your configured profile in Thunderbird.
Method 2- Verify the firewall settings
Sometimes, antivirus and firewall application blocks the messages of Thunderbird. Therefore, the user needs to disable the anti-virus or even firewall software and then try sending messages. You can even try changing the port number after consultation with the service provider.
Method 3- Reconfiguring the Thunderbird application
The problem can be resolved by reconfiguring Thunderbird email account and deleting the old login details.
- Update the Thunderbird email client application to the latest version.
- Once you have updated, send mail once again to see if the issue persists.
- If it persists, select Menu tab >> option.
- From select security >> password >> Saved Password tab.
- Delete the old password and once again configure the account. Now, try to send mail once again. It will help you to reconfigure your account and set a new password.
Final Words
In this blog, we have provided the methods to resolve the SMTP error. If you are still facing the same problem after using this method, now need to switch to another email client. You can try eSoftTools Thunderbird to Outlook Converter that will allow you to smoothly & directly move all emails to Outlook PST and various other file formats.
Also Read:- How to Export Thunderbird to Outlook?