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5.7.0 Must Issue a Starttls Command First Thunderbird  

Do you get the ‘The mail server responded: 5.7.0 must issue a starttls command first thunderbird error frequently on your Thunderbird email client? Then proceed with the troubleshooting steps given on our site to fix the error.

Method 1: Checking the SMTP settings

  • On your computer, launch the Mozilla Thunderbird email client first.
  • Next, give a right-click on your email account available at the left-side panel.
  • Select the Settings option from the pop-up menu.
  • This will open the Account Settings window on your Thunderbird email client.
  • Select your email account from the displayed list and click the Server Settings button to check the server settings.
  • Navigate to the left-side panel and click the Outgoing Server (SMTP) tab.
  • In the Outgoing Server (SMTP) window, you can modify the SMTP settings for your account.
  • Select your account from the displayed list and click the Edit button to access the SMTP Server window.
  • Make sure that the STARTTLS option is selected in the Connection security drop-down menu.
  • Verify whether you have entered the appropriate port number for the selected encryption type.
  • Check whether you have entered the correct email address in the Server Name field.
  • Click OK and try sending a test email. Check if the error 5.7.0 must issue a starttls command first thunderbird has been resolved.
 

Method 2: Removing and reinstalling the Mozilla Thunderbird app

  • On your Windows computer, open the Control Panel app and click on Programs and Features.
  • Select the Uninstall a program option and choose the Thunderbird program from the displayed list.
  • Click the Uninstall/Change button and confirm your action.
  • After uninstalling the Thunderbird app, reinstall it.
  • Add your email account again in the Thunderbird email client and check if the problem has been resolved.
  • If the 5.7.0 must issue a starttls command first thunderbird problem persists, contact our technical support team.
5.7.0 must issue a starttls command first thunderbird