Troubleshooting Email - Enable SMTP Authentication | Bluehost Support
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Troubleshooting Email - Enable SMTP Authentication


Occasionally, your Email Client will require SMTP authentication for your email account to work correctly. With SMTP authentication set up, you reduce the risk of receiving mass amounts of unsolicited spam emails and prevent your server from being exploited as an open mail relay.

Enabling SMTP Authentication

Instructions for enabling SMTP authentication will vary depending on the email client being used. We have provided the steps below for a few popular email clients.

Microsoft 365

  1. Open the Office 365 admin center.
  2. Click the Users option from the menu to the left, then choose Active users.
  3. Select the user, and in the menu that pops out to the side, click the Mail tab.
  4. Click Manage email apps under the Email apps option. 
    Microsoft 365 - Email Apps option
  5. Verify the Authenticated SMTP setting, and click Save.

Microsoft Outlook Express

  1. From the Tools menu, choose Accounts.
    Microsoft Office 365 - Email Apps section
  2. Click the Mail tab.
  3. Select your email address from the list of accounts, then click the Properties button.
    Properties button
  4. Click the Servers tab.
    Servers tab
  5. Under Outgoing Mail Server, check the box next to My server requires authentication.
  6. Click on the Settings button, and ensure Use the same setting as my incoming mail server is selected.
    Server Settings window
  7. Click OK, then Apply the changes.
  8. Click Close to complete the configuration.

Outlook 2013 and 2016

  1. Open your Outlook account.
  2. From the Tools menu, choose Account Settings.
  3. Select your email account from the list, then click Change.
  4. On the Change E-mail Settings window, click More Settings.
  5. Click the Outgoing Server tab, then check the My outgoing server (SMTP) requires authentication option.
    Outgoing Server tab
  6. Click the Advanced tab, and change the Outgoing server (SMTP) port.
    Advanced tab

    Note: If you want to use SSL, change the port to 465 and select SSL from the encryption drop-down menu. If you don’t want to use SSL, then change the port to 587.

  7. Click Ok, then click Close when you have completed the configuration.

Apple Mail

  1. Open the Mail program.
  2. From the Mail menu, choose Preferences
  3. Click the Accounts icon, and choose the Account information tab.
  4. Click on the Outgoing Mail Server (SMTP) Server List option, then select Edit SMTP Server List from the drop-down menu.
    Outgoing Mail Server setting
  5. Click the Advanced button.
  6. Make sure you have the correct SMTP server selected at the top and verify that Authentication is set to Password.
    Username and Password settings
  7. Click OK, then click the red dot to close your window. 

Mozilla Thunderbird

  1.  Open your Mozilla Thunderbird client.
  2. From the Tools menu, select Account Settings.

    Alternatively, you can right-click on the email account and choose Settings.

    Account Settings
  3. Select the Outgoing Server SMTP from the menu to the left.
  4. Highlight the email account you would like to edit, and click Edit.
    Edit Email Account
  5. From the Connection security drop-down menu, select either SSL or None.
  6. From the Authentication method drop-down menu, select Normal password.
    Authentication Method setting
  7. Click the OK button. 


  1. Log in to your Gmail Account.
  2. In the top lefthand corner, open the Settings by clicking the Gear icon, then click See all settings.
  3. Click Accounts and Import.
  4. Select the Email account you need to update, then click edit info.
  5. Update the Name if needed and click on the checkbox Treat as an Alias. To learn more about Gmail Alias, you can visit their help article here.
  6. Enter the SMTP Server and your full email address as the Username.
  7. Enter Password for your email account.
  8. Choose Port 465 (SSL).
  9. Select Secured connection using SSL (recommended).
  10. Click Save Changes once you're done.

If you need further assistance, feel free to contact us via Chat or Phone:

  • Chat Support - While on our website, you should see a CHAT bubble in the bottom right-hand corner of the page. Click anywhere on the bubble to begin a chat session.
  • Phone Support -
    • US: 888-401-4678
    • International: +1 801-765-9400

You may also refer to our Knowledge Base articles to help answer common questions and guide you through various setup, configuration, and troubleshooting steps.