Enable SMTP AUTH for specific mailboxes Open the Microsoft 365 admin center and go to Users > Active users. Select the user, and in the flyout that appears, click Mail. In the Email apps section,

For sending and receiving messages, we use two protocols one is SMTP (Simple Mail Transfer Protocol) and another is POP3 (Post Office Protocol version 3) . … Difference between SMTP and POP3: S.NO SMTP POP3

Note that blocking TCP 445 will prevent file and printer sharing – if this is required for business, you may need to leave the port open on some internal firewalls. If file sharing is needed

For sending and receiving messages, we use two protocols one is SMTP (Simple Mail Transfer Protocol) and another is POP3 (Post Office Protocol version 3) . … Difference between SMTP and POP3: S.NO SMTP POP3