- 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.
