Mozilla Thunderbird is one of the leading email clients that is used to manage multiple email accounts under a single platform. If the email server settings are incorrect, Thunderbird won't connect to mail server. Go through the troubleshooting steps given below to fix the mail server issues with your Thunderbird app.

  • Step 1 : On your Windows computer, launch the Thunderbird app after ensuring that you have a stable Internet connection.
  • Step 2 : Next, click the Tools tab and select the Accounts Settings option from the drop-down list.
  • Step 3 : In the Account Settings window, click the Outgoing Server (SMTP) tab from the left-side panel and check the outgoing server settings under the Details of selected server section.
  • Step 4 : Also, check whether you have entered the correct email address in the Account Name and Email Address fields.
  • Step 5 : Click OK and check if the problem has been resolved.
  • Step 6 : Ensure that no firewall or antivirus software is blocking your Thunderbird app from connecting to the mail server.
  • Step 7 : If necessary, run Thunderbird with add-ons disabled. To do so, click the Help menu and select the Restart with Add-ons Disabled option.
  • Step 8 : If you cannot restart the app with add-ons disabled, Thunderbird won't connect to mail server.
  • Step 9 : Click the Start menu available at the bottom-left corner of the desktop and select Mozilla Thunderbird (Safe Mode) to run the app in Safe mode.
  • Step 10 : If you cannot see Thunderbird in the Start menu, launch the Run dialog box by pressing the Windows + R shortcut keys.
  • Step 11 : Type 'thunderbird-safe-mode' in the Run dialog box and hit Enter to launch the Thunderbird app in Safe  mode.
  • Step 12 : If the Thunderbird won't connect to mail server problem remains unsolved, remove and reinstall Thunderbird on your computer.