Microsoft 365 is switching off basic SMTP sign-in: keep printers, scanners and apps sending email
What's changing
Many office devices send email through Microsoft 365 by signing in with a plain username and password. Microsoft calls this Basic Auth for SMTP AUTH. At the end of December 2026 it will be switched off by default for existing Microsoft 365 (Exchange Online) accounts.
Your admin can turn it back on for now. Microsoft will announce a final removal date in the second half of 2027, so turning it back on only buys time.
What you'll notice
Anything that sends email with a saved username and password stops sending:
- scan-to-email on copiers and scanners
- printers that email alerts or scanned documents
- older apps and systems that send email (invoices, reminders, notifications)
Which fix fits each device
Go through the questions in order for each device or app, and stop at the first "yes".
- Does the device or app support OAuth (modern sign-in)? Use it. Check the settings or ask the manufacturer for an update; this is the simplest fix and keeps sending through Microsoft 365.
- Does it only send to people inside your company? Use Microsoft's internal-only sending option, which delivers to your own mailboxes without a username and password.
- Does it send to outside recipients from a fixed IP address? Set up a connector (relay) in your Microsoft 365 that accepts mail from that address and sends it on.
- None of the above? Use a third-party SMTP relay service and point the device at it.
Switching to a relay? Add it to your SPF record: check your SPF record.
Questions
When does this happen?
At the end of December 2026, Microsoft turns off basic SMTP sign-in by default for existing Microsoft 365 (Exchange Online) accounts. An admin can turn it back on for now. Microsoft says it will announce a final removal date in the second half of 2027.
How will I know it has affected us?
Devices and programs that send email with a saved username and password stop sending. The usual signs are scan-to-email failing on a copier or scanner, a printer that no longer emails alerts, or an older app that stops sending messages.
Can we just turn it back on?
For now, yes: an admin can re-enable it. That only buys time, because Microsoft plans to remove it for good and will announce that date in the second half of 2027. Moving each device to one of the options on this page is the lasting fix.