I wondered that first but having Postfix set up for Exchange server (I follow docs I find on the net) which setup seems like a "regular" relay, I cannot relay. I get: ... Trusted TLS connection established to smtp.office365.com[52.98.145.98]:587: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits) 35F71C0145: SASL authentication failed; server smtp.office365.com[52.98.145.98] said: 535 5.7.139 Authentication unsuccessful, the request did not meet the criteria to be authenticated successfully. Contact your administrator. [LO4P123CA0460.GBRP123.PROD.OUTLOOK.COM] Trusted TLS connection established to smtp.office365.com[52.97.129.66]:587: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits) ... When I ran quick sroogle for that error what I read points to MFA, I figured. It also is not a mis-configured auth because for that Exchange server says: ... 8A2F0C0146: SASL authentication failed; server smtp.office365.com[52.97.208.50] said: 535 5.7.139 Authentication unsuccessful, the user credentials were incorrect. [LO4P123CA0072.GBRP123.PROD.OUTLOOK.COM] ... Both IMAP & SMTP Exchange server requires OAuth2 and it might be that where I'm failing, as I still have to investigate.
many thanks, L Sent from Mailspring (https://getmailspring.com/), the best free email app for work On Oct 4 2021, at 3:13 pm, Viktor Dukhovni <postfix-us...@dukhovni.org> wrote: > On Mon, Oct 04, 2021 at 02:17:33PM +0100, lejeczek wrote: > > > Is relaying to an Exchange Online servers which - in my case is > > imposed as I'm a member of an org - employ MFA, possible with Postfix? > > Unlikely. Postfix supports SASL, I don't know what would constitute > "MFA" with SASL. > > > On Exchange's side - I'm looking at sign-in methods available to me > > and among those is "Authenticator app" - which, is Postfix is capable > > of MFAs, would be a way forward I guess. > > Are you sure the MFA requirement is for email submission, rather than > administrator access? > > -- > Viktor. >
