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Thunderbird Won’t Let Me Send Email – Easy Solutions for You

Is There A Problem With Thunderbird Email?

Thunderbird Won’t Send Email supported by Mozilla, but now they are on their own.

Thunderbird is considered a moderately safe email client. But sometimes you might face issues while trying to send emails via Thunderbird. It can be a result of wrongly put settings.

So if Thunderbird isn’t let you send emails, this article surely will help you to get rid of this problem. If you are failing in sending messages via Thunderbird, here we provide a series of methods by following which you might resolve the issue.

Thunderbird Sending Of The Message Failed

A lot of people are reporting that this issue started with the version 78 update of Thunderbird. To undo this problem, check if your antivirus or firewall is blocking the latest version or not, or whether the email provider is still using the backdated TLS security protocols.

Thunderbird Sending Of The Message Failed
Thunderbird Sending Of The Message Failed

If your antivirus is blocking Thunderbird’s latest version, make Thunderbird an exception in your antivirus program and restart your computer. I hope this will solve this annoying issue of yours.

Thunderbird Outgoing Mail Not Working

This is a common problem of being able to receive emails but unable to send emails. If this happens, you will see a message saying ‘try again’. Well, this happens because of an SMTP server error.

In this case, you need to reset the SMTP server settings of the Thunderbird email.

Where Are The Outgoing Server Settings In Thunderbird?

SMTP server is the server that manages the total email delivery process. So if the settings are not set in the proper way, it may result in an error.

In order to get rid of this problem, you need to set the settings properly. Until you set the setting properly, Thunderbird won’t connect to the mail server.

Follow the steps to know what to do when Mozilla Thunderbird won’t send an email.

Check if the settings are proper –

  • Open the Mozilla Thunderbird on your computer.
  • Click on Tools.
  • Choose Account Settings.
  • Click on Outgoing Server (SMTP).
  • Check whether the SMTP Server Settings are proper for the configured email ID or not.
  • Ensure the email service provider’s website and search for Mail Settings > SMTP.

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)
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.

Thunderbird Send Button Not Working

There can be a problem with the send button of Thunderbird email. It could be missing from the window, or it can simply grey out. Here are the solutions to these problems.

Thunderbird Send Button Not Working
Thunderbird Send Button Not Working
  • Thunderbird Send Button Missing

If Thunderbird send button is missing from your window, you can add it in the Composition Toolbar. Go to the View, then click on Toolbars > Customize, and drag the send button onto the toolbar.

You can use the Restore Default Set button in customize window if the above process does not work for you.

  • Thunderbird Send Button Greyed Out

The send button remains ‘greyed out’ until you put a valid email ID in the ‘To’ section. Until the window gets the receiver’s email ID, the send button won’t work. And if you are offline by any chance, the button remains grey in color.

To get rid of this problem, make sure you are online and have put the proper receiver’s email ID in the required field.

Thunderbird Outgoing Server Settings Gmail

Use the following settings to configure Thunderbird outgoing server with Gmail.

  • Server name: smtp.gmail.com.
  • Port: 587.
  • Use name and password: your thunderbird credentials.
  • Username: Your Gmail user ID.
  • Connection security: STARTTLS.

Certificate Thunderbird Email

Go to Mozilla Thunderbird > Tools > Options > Advanced > Tab Certificates > View Certificates > Tab Servers > Add Exception.
Put the name of the mail server of which you want a certificate. Click on the Get Certificate button.

The Final Words

We hope that we did provide all the solutions for your Thunderbird email-related issues. Hope you will be able to send emails now without any hassle.

Also Read: How to Sign in To Your Cox Email Account – Easy Cox Email Sign In


Hi there, My self Aniket Jain. A virtual SEO expert, content writer, and digital marketer. Works with lots of passion, hardly dedicated to what's best and what's next ✌️. Hope u all like my work ✌️

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