Thunderbird Connection To Server Was Reset [Easy Fixes 2024]

Written By Steven Arends

Mozilla Thunderbird is a free, open-source, cross-platform application for managing email, news feeds, chat, and newsgroups. Most thunderbolt consumers use it for its excellent useable features.

But sometimes, users face Thunderbird connection to server error without any types of previous warning signs. For ordinary users like us, it can be a bit frustrating. As it turns out, there can be several different reasons that might cause this error.thunderbird-connection-to-server-was-reset

Don’t worry. This post provides 6 simple methods to eliminate the Thunderbird Connection To Server Was Reset issue.

So, let’s get started.

Why Does Thunderbird Connection to Server Error Occur?

Mostly antivirus errors, two-factor authentication issues, and modified versions of Thunderbird are the main reasons behind this connection to server error case. Besides, Proxy server bugs, Antivirus Mail shield issues, and Network connection problems are the secondary causes of this error.

It can be a bit of a hassle to find out all the problems at once. So, I did some research and tracked down all the reasons.

Here are the reasons why Thunderbird connection to server error occurs: 

Antivirus Errors

Antivirus has many kinds of protection systems. Sometimes this antimalware system can block the connection between the Thunderbolt client and the internet, which can cause this connection to a server error.

Two-Factor Authentication Issues

If your email has Two-Factor Authentication enabled, it could interfere with your login process to your Thunderbird client. It stops the login request from the modified version of the Thunderbird client rather than their Official client.

Modified Versions of Thunderbird

Windows firewall can detect the modified versions of any software. When you use a modified version of Thunderbird, it will block your Thunderbird client.

Proxy Server Bug

Sometimes Proxy server has a connection bug. This bug stops the connection between the Thunderbird mail server and the Proxy server, which will be another cause of this error.

Antivirus Mail Shield Issue

Some premium versions of antivirus come with a mail protection module that can block ongoing or outgoing emails for security reasons.

Check out the easiest way to Fix Thunderbird Not Receiving or Sending Emails

How to Fix Thunderbird Connection To Server Error

Turning off two-factor authentication, Reinstalling the antivirus, Stopping the Proxy server, Disabling the antivirus mail shield, Whitelisting the Email Client, and changing the network DNS settings can solve this error.

To know them in detail, read along.

Here are the methods to fix Thunderbird connection to server error:

1. Turn Off Two-Factor Authentication

Sometimes Two-Factor Authentication does not allow you to log in to your Thunderbird account for security reasons. You can fix this issue by turning it off.

Here are the steps to turn off two-factor authentication:

  • Log into your Google account from your preferred device.
  • Tap the upper right corner icon and select Manage your Google Account.
  • Click on the Security option from the top.
  • Click Signing in to Google and tap 2-Step Verification.
  • Tap the Turn Off button.turn-off-two-factor-authentication
Important Note: Google Two-Factor Authentication is a safety measure to stop your email address from getting stolen. So, it will be a security threat to you if you have to turn it off.

2. Reinstall Antivirus

Antivirus can interfere with the connection between the Thunderbird client and the internet connection. Reinstalling the antivirus can solve this error.

Follow the below step-by-step process to reinstall the antivirus:

  • Open Control Panel from the Start menu.
  • Select Uninstall a Program from Programs.uninstall-a-program-from-programs
  • Choose your Antivirus and click to Uninstall the program.
  • Download the latest version of your desired
  • Install Antivirus from setup.exe file.

Related guide: how to Export Thunderbird Emails to Outlook.

3. Stop Proxy Server

Proxy servers sometimes create issues between the network and server which can lead to this connection to a server error. Stopping the Proxy server can solve this issue.

Here are the steps to stop the Proxy server:

  • Press the Winows+I key to open Settings.
  • Select the Network & Internet option from
  • Click the Proxy tab and turn off the Proxy server.


4. Disable Antivirus Mail Shield

A mail shield can block the communication between the mail server and the client-server, which causes the server error. Disable the Antivirus mail shield will remove this error.

Follow the steps below to disable the Antivirus mail shield:

  • Open your Antivirus program from your computer.
  • Open Settings from the Antivirus dashboard.
  • Select Protection from the left drop-down list.
  • Choose Mail Shield under Configure Shield Settings.
  • Uncheck the box associated with Enable Mail Shield.
  • Click on Stop permanently from the new menu to disable it.

5. Whitelisting the Email Client

Windows defender can block your connection if you use the modified version Thunderbird client. So, allowing the modified client in the defender will solve this unwanted issue.

Here are the steps to allowing the email client in Windows Defender:

  • Open up a Run dialog box by tapping the WIN+R button on the keyboard.
  • Type control firewall.cpl in the dialog box and press Enter.control-firewall-cpl-run
  • Click on Allow an app or feature through Windows Defender Firewall from the Windows Defender Firewall menu.
  • Choose the Change Settings button inside the Allowed app menu.
  • Click on Yes at the UAC (User Account Control) prompt to allow admin access to the app.
  • Scroll down the list of applications and see if Thunderbird is present among the list of permitted items.
  • Click on Allow another app and navigate to where you installed Thunderbird if it’s not found in the list of applications.
  • Check both the Private and the Public boxes associated with the Thunderbird entry before saving the changes.

6. Change Network DNS Settings

Sometimes IPv6 creates problems in the Thunderbird client. So, disabling IPv6 can solve this problem.

Follow the below steps to change the network DNS settings:

  • Open Thunderbird from your device and choose Options.
  • Select General from Options.
  • Go to Configure Editor from the lower right corner.configure-editor
  • Modify settings by allowing the risks.
  • Type IP in the search box To locate settings.
  • Switch to true in DNS.disableIPv6.


How did you fix the connection to the server reset while the page was loading?

Clear cache and remove cookies will solve this issue. Go to Firefox/Tools > Options > Advanced > Network > Cached Web Content: Clear Now.

What does the connection to the server was reset mean?

Connection to the server reset means the server can not transmit your data to your browser.

How do I connect  Thunderbird to the server?

If this happens, log in to your thunderbird account via your web browser. Then restart the Thunderbird app and try to log in again.

Final Thought

To wrap things up, Thunderbird is an essential softwares for users who want to manage their email, news feeds, chat, and newsgroups in one place.

In this article, I explained the reasons behind the connection to the server error and 6 tested methods to fix it. Hopefully, this article has helped solve the Thunderbird connection to the server error.

If you have any suggestions, ideas, or queries, comment below.

About The Author
Steven Arends is a computer science graduate and tech enthusiast with over 10 years of experience in the field. He has a vast collection of computer hardware and loves exploring the latest advancements. As a contributing author to 10Scopes, Steven shares his expertise to make the world of technology more accessible and easier to understand for all readers.

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