Forum Discussion
Need help with scan-to-email function on printer
hi barooder Based on the testing you've done, the SMTP AUTH settings themselves appear to be enabled, so the 535 error needs further investigation.
One important clarification: Microsoft's current SMTP AUTH deprecation timeline does not say Basic SMTP AUTH was removed in April 2026. The January 27, 2026 Exchange Team update says that, for existing tenants, Basic SMTP AUTH remains unchanged until December 2026 and will then be disabled by default. Administrators can still enable it during that transition.
So I wouldn't use the Basic Auth retirement as the explanation for this failure yet.
At this point, the most useful next step would be checking the Exchange Online SMTP AUTH client submission logs/report and Entra sign-in logs for the failed authentication attempt. That should help identify whether Exchange is actually receiving the LOGIN attempt and what is causing the 535 response.
The fact that `SmtpClientAuthenticationDisabled` is `False` at both organization and mailbox level is useful, but it doesn't by itself tell us why this particular authentication attempt is being rejected.