The features supported by each email client programs vary. Users can use any email programs that support POP3 and IMAP4 to connect to Exchange Online (for example, Outlook, Windows Mail, and Mozilla Thunderbird). Disabling Basic authentication will block legacy protocols, such as POP and IMAP. To protect your Exchange Online tenant from brute force or password spray attacks, your organization will need to Disable Basic authentication in Exchange Online and only use Modern authentication for Outlook in Exchange Online. For more information, see What are security defaults?. All rights reserved.If you've enabled security defaults in your organization, POP3 and IMAP4 are automatically disabled in Exchange Online. Outlook 2003® is a registered trademark of Microsoft Corporation in the United States and/or other countries. NOTE: As a courtesy, we provide information about how to use certain third-party products, but we do not endorse or directly support third-party products and we are not responsible for the functions or reliability of such products. Go to the Advanced tab, and then change the Outgoing server (SMTP) port to 80 or 3535.The following example assumes you did not change your SMTP relay section in your Manage Email Accounts page. If you changed the user name and password in the SMTP relay section of your Manage Email Accounts page, select Log on using and enter the user name and password. If you did not change the SMTP relay section, select Use same settings as my incoming mail server.

Select My outgoing server (SMTP) requires authentication.On the Internet E-mail Settings window, go to the Outgoing Server tab.Contact your Internet Service Provider to get this setting. If you do not have SMTP relay set up and your Internet Service Provider (ISP) allows it, you can use the outgoing mail server for your Internet Service Provider. Log on to your Manage Email Accounts page to set up SMTP relay. In order to use this server to send e-mails, you must first activate SMTP relay on your e-mail account. Incoming mail server (POP3) POP, or IMAP,. On the Internet E-mail Settings (POP3/IMAP) window, enter your information as follows:.For your server type, select POP3 or IMAP, and then click Next.On the E-mail Accounts wizard window, select Add a new e-mail account, and then click Next.In Microsoft Outlook, from the E-mail Accounts menu, select Tools. To Set Up Your E-mail Account in Microsoft Outlook You can set up previous versions of Microsoft Outlook by using the settings in this tutorial. This tutorial focuses on setting up Microsoft Outlook 2003, but these settings are similar in other versions of Microsoft Outlook. This tutorial shows you how to set up Microsoft Outlook 2003® to work with your e-mail account. Setting Up Your POP or IMAP Email Address in Microsoft Outlook

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