Hello, As a possible workaround: with Microsoft Graph API you can send emails, with an api token which does not need to be renewed. But it needs some scripting, and does not require any smtp server.
On Sun Nov 30 11:11:33 2025, Jean-Marc Annonier wrote: > Hello all, > > First forgive me if this topic has already been addressed, if there is a > readily available solution, please let me know! > > For the last 3 years, I've been happily using Opensmtp as an internal relay > to send all my emails from internal hosts via my M365 mailbox. > > On the internal side: Wordpress sites, backup services, virtualisation > services, etc all connecting to Opensmtp with no authentication, no > encryption. Then Opensmtp sends these emails using smtp+tls as shown below. > Sample config: > ------------------- > table secrets file:/etc/mail/secrets > listen on 0.0.0.0 inet4 port 25 > action "relaymydomain" relay host smtp+tls:// > [email protected]:587 auth <secrets> > match from mail-from "[email protected]" for any action "relaymydomain" > > Very easy and very efficient! > > Unfortunately, Microsoft is about to break everything with the > deprecation of Basic Authentication starting from March 2026: Exchange > Online to retire Basic auth for Client Submission (SMTP AUTH) | Microsoft > Community Hub > <https://techcommunity.microsoft.com/blog/exchange/exchange-online-to-retire-basic-auth-for-client-submission-smtp-auth/4114750> > > All authentication now needs to be done through OAuth2 tokens, and unless I > am mistaken, Opensmtp doesn't support OAuth2. I've seen there may be > filters but I don't know where to find them. > > I can fix the Wordpress websites with new plugins that support OAuth2 > (WPO365 is very good). But for older services that don't support OAuth2, > I'm stuck. I've been looking for alternatives on Github but couldn't find a > universal solution. > > As I'm probably not the only one with this problem, I thought I'd reach to > the group to see if anyone has a working solution. > > Thanks heaps! > > Jean-Marc -- Best regards Maksim Rodin С уважением, Родин Максим
