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MFP can no longer mail via Microsoft 365

Basic auth disabled on M365, MFP needs SMTP relay.

Try this first

  1. 1SMTP AUTH client submission (smtp.office365.com:587) needs basic auth and an exempted mailbox account; not viable when MFA is enforced tenant-wide. High Volume Email (smtp-hve.office365.com) is a separate direct-send service for servers and devices.
  2. 2Better: direct send (no auth) or send connector on fixed IP
  3. 3Alternative: local SMTP relay (hMailServer/Postfix) as bridge

When to bring us in

External recipients needed too, use licensed mailbox + send connector.

See also

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