Microsoft 365 SMTP relay SMTP Settings (Server, Port & Setup)

To send through Microsoft 365 SMTP relay, use these SMTP settings.

Microsoft 365 SMTP relay SMTP settings

• Server: smtp.office365.com
• Port: 587 (STARTTLS)
• Auth: a licensed mailbox with SMTP AUTH enabled

Deliverability still matters

Correct SMTP settings get mail accepted, but SPF, DKIM, DMARC and a clean sending reputation decide whether it lands in the inbox.

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