Send & Receive Issues

Fix Office 365 Scan-to-Email SMTP Failure and TLS Issues

Maira Mehtab Sep 22, 2026 869 views

Question details

Users are experiencing widespread scan-to-email failures across multiple organizations despite having correct network and SMTP configurations.

Product: Microsoft Office 365
Device & OS: not provided
Scenario: Attempting to use the scan-to-email feature via Office 365 SMTP authentication.
Observed behavior: SMTP connections fail unexpectedly, preventing scanned documents from being emailed, likely due to disabled TLS 1.2 cipher suites.

Before you start

Verify your printer or scanner's firmware is up to date and check the Microsoft 365 admin center for any active service advisories related to Exchange Online.

Solution 1Recommended

Verify TLS 1.2 Cipher Suites and Contact Microsoft Support

Address potential TLS 1.2 cipher suite deprecations by checking device compatibility and escalating to Microsoft.

Recent scan-to-email failures are often linked to Microsoft disabling specific older TLS 1.2 cipher suites without prior broad communication. If your basic SMTP settings are correct, the hardware may be failing the TLS handshake.

Check Device Compatibility

Review your scanner or multifunction printer's administrative web interface to ensure it supports the latest secure TLS 1.2 cipher suites.

Gather Diagnostic Data

Collect detailed SMTP logs, exact failure timestamps, specific error codes, and models of the affected devices from your network.

Open a Support Case

Log into the Microsoft 365 Admin Center, navigate to Support, and open a new service request providing the gathered logs to escalate the tenant-side TLS issue.

Service Advisories: Keep an eye on the Microsoft 365 Service Health dashboard, as widespread issues affecting multiple tenants are typically updated there.

Solution 2

Configure an Alternative SMTP Relay

Set up a direct send or SMTP relay connector as an alternative if SMTP client submission continues to fail.

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Frequently Asked Questions

Why did Office 365 scan-to-email suddenly stop working?

Microsoft frequently updates backend security protocols. The sudden deprecation or disabling of specific older TLS 1.2 cipher suites can cause older scanners and multifunction printers to fail the security handshake, dropping the connection.

What ports are required for Office 365 SMTP AUTH?

SMTP AUTH for Office 365 typically requires port 587 with STARTTLS encryption enabled. Port 25 can also be used for direct send or SMTP relay configurations depending on your network setup.

How can I check if my scanner supports the required TLS versions?

Access your scanner's web interface by typing its IP address into a browser. Navigate to the network, security, or email settings, and look for SSL/TLS configuration options to verify the supported versions.

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