(I have asked this question also on stackoverflow but I now think that this might be a more useful community to ask hence I am also posting here.)

I am trying to know whether it is possible to enable SMTP to use OAUTH2.0, but with basic AUTH disabled. Is it possible to do this? If so, can I please get some point-by-point instructions on how to go about this? I want it such that linux users who do not want to use graph-based services or the web-based outlook or evolution can use it. Thank you very much in advance!

1 Answer 1


What is your client? You could refer to the following article: Authenticate an IMAP, POP or SMTP connection using OAuth https://docs.microsoft.com/en-us/exchange/client-developer/legacy-protocols/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth

  • My client is mutt that can be configured to use SMTP with OAUTH2.0 (and I think that I know what can be done from the client side). However, my question is server-side, specifically, whether and how my organization can disable basic AUTH for SMTP (for all users) while enabling SMTP with modern OAUTH2.0 (for specific mailboxes).
    – user663702
    May 10, 2021 at 5:50
  • Office 365? As of February 2020, OAuth authentication is available for POP3, IMAP4, and SMTP AUTH connections to Exchange Online. The SMTP AUTH protocol is used for client SMTP email submission, typically on TCP port 587. SMTP AUTH supports modern authentication (Modern Auth). So your Office 365 org is supported it when the clients use SMTP AUTH. Use Exchange Online PowerShell to enable or disable SMTP AUTH on specific mailboxes Set-CASMailbox -Identity <MailboxIdentity> -SmtpClientAuthenticationDisabled <$true | $false | $null>
    – Jayce
    May 14, 2021 at 3:00

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .