Connect Outlook or Microsoft 365 to Revnio: what works

Before you start

• Personal addresses (outlook.com, hotmail.com, live.com, msn.com): Microsoft’s support notice says that after its cut-off date, connecting to Outlook.com with Basic authentication (a plain password) fails and modern sign-in is required. Revnio cannot use modern sign-in for Microsoft yet.
• Microsoft 365 work or school addresses: sending with a password uses “SMTP AUTH”. Microsoft recommends turning it off for the organization and enabling it only for the mailboxes that need it. It is already off if the organization uses security defaults, and it is blocked if an authentication policy disables basic authentication for SMTP.
• An admin has to enable it for your mailbox. Microsoft’s article “Enable or disable authenticated client SMTP submission (SMTP AUTH) in Exchange Online” describes the organization-wide and per-mailbox settings.
• If your sign-in requires multi-factor authentication, a plain password login is unlikely to work. We could not confirm whether your admin can issue app passwords for Microsoft 365.

Step by step

1. Ask your Microsoft 365 admin to enable “authenticated SMTP” (SMTP AUTH) for your mailbox.
2. In Revnio, open “Any email account”, enter your address and the mailbox password your admin tells you to use, and click “Connect and send me a test email”.
3. If you see “rejected the login”, password sending is not allowed for this mailbox. Do not keep retrying.
4. Alternative: use another mailbox for recovery emails (for example a company mailbox on a provider listed in the guide), or let Revnio send from its own address, which needs no setup.

Server settings

Revnio fills these in when it recognizes your provider. Enter them yourself under Advanced settings if it does not.

If it doesn’t work

• “Rejected the login”. For personal Outlook.com addresses Microsoft no longer accepts password sign-in from apps like this. For work addresses, ask your admin whether authenticated SMTP is enabled for your mailbox and whether your organization allows password sign-in.
• Microsoft returns “550 5.7.30 Basic authentication is not supported for Client Submission”. This is a third-party report of Microsoft’s message when basic authentication is turned off. Your admin must enable SMTP AUTH for the mailbox, or you need a different mailbox.
• It used to work and stopped. Microsoft said that by the end of December 2026 SMTP AUTH with a password will be turned off by default for existing organizations (admins can still enable it), and a final removal date is to be announced in the second half of 2027. Plan to use a different mailbox.

Taking the access back

• Remove the saved connection with Disconnect in Revnio. If your admin created a dedicated password or enabled SMTP AUTH just for Revnio, ask them to switch it off.

Sending limits

Not documented in the sources we could check. Revnio stops sending through your mailbox once it has sent this many recovery emails in 24 hours, and sends the rest through Revnio’s own sender so nothing is delayed. These caps are conservative Revnio defaults, not limits set by the provider. For Outlook the cap is 300 a day.

What we could not confirm

We checked this page against the provider’s own help where we could find it. These details we could not confirm from an official source, so check them with your provider:

• Whether consumer Outlook.com still supports app passwords for sending. We found nothing that says it does.
• The year of the Outlook.com Basic-authentication cut-off in Microsoft’s support notice, and the exact server for consumer accounts (third-party guides list smtp-mail.outlook.com; Revnio’s preset uses smtp.office365.com).
• Whether Microsoft 365 admins can issue app passwords, and the exact admin-center menu path.
• The December 2026 and 2027 dates come from Microsoft’s January 2026 update as reported by secondary summaries; confirm on Microsoft’s own page.

Official sources

• Microsoft Learn: Enable or disable authenticated client SMTP submission (SMTP AUTH)
• Microsoft Tech Community: Exchange Online to retire Basic auth for Client Submission (SMTP AUTH)
• Microsoft Support: Outlook and other apps are unable to connect to Outlook.com when using Basic authentication