Help guide
Microsoft 365 is turning off SMTP passwords. Will your invoices still send?
Many small-business apps send invoices "from your email" by logging into your mailbox with a username and password over SMTP. Microsoft is retiring that method for Microsoft 365.
What's changing
- End of December 2026: Microsoft plans to turn off SMTP basic authentication (username and password) by default for existing Microsoft 365 organizations.
- Administrators can switch it back on for now, so the first break is soft. Microsoft has delayed this change before, and plans to announce a final removal date in the second half of 2027.
- New Microsoft 365 organizations created after the change won't have password-based SMTP at all.
Who's affected
Any app where you typed your Microsoft 365 email address, an SMTP server like smtp.office365.com, and your password to "send from your own address." If the app offers a Sign in with Microsoft button instead, you're fine.
What to do
- Check your apps now. Look at the email settings in your accounting, invoicing and booking software. Password fields and an SMTP server mean it's affected.
- Look for a Microsoft sign-in option. Many vendors have added one. Switch to it if it's there.
- Ask your IT person about a relay. Microsoft and several vendors offer ways for older apps to send mail without a password.
- Send invoices through a connector. Tools can send your invoices straight from your Microsoft 365 mailbox with a secure sign-in, so they also land in your Sent Items.
Send invoices through Microsoft 365 the new way
We're gauging interest in tools that send invoices from Zoho Books, Manager.io and other apps through your Microsoft 365 mailbox with a secure Microsoft sign-in instead of a password.
See our Outlook senders