Forum Discussion
SMTP XOAUTH suddenly failing for Outlook personal with '535 5.7.3 Authentication unsuccessful'
A better workaround, because that is what this is, is to not use Outlook accounts anymore because they are not supported, even not if you can't send messages anymore when using OAuth and an universal email protocol like SMTP.
Moreover, Microsoft is trying to move people away from password authentication, for good reasons, and therefore it is pretty unbelievable that OAuth doesn't work for SMTP anymore, and that nobody cares. When using password authentication it works fine.
If you think that my advice is to stop using Outlook is overdone, no I don't think so. The previous problem, IMAP IDLE (=push messages) not working anymore took Microsoft almost three months to recognize and fix. That's pretty pathetic and unprofessional.
So, this is not about emotions, but about facts. Outlook/Hotmail/Live is unreliable for anything which has any significance.
There are a million Members in the MTC - only we discuss, I am a little surprised by the lack of a solution
- Actually no. I'm currently working on learning MailKit usage in PowerShell, but using EXO/M365/Entra to do this, rather than personal Outlook. I just came across this page as I was earlier having the same 535 5.7.3 Authentication Unsuccessful error. I got past it, and it was unrelated to your original issue's solution. But couldn't help but notice how you were getting actively deflected and want to let you know I could see that and thought it was ridiculous.
JeremyTBradshaw did you see this recent issue?
https://answers.microsoft.com/en-us/outlook_com/forum/all/user-is-authenticated-but-not-connected/7d8465ec-9906-4733-8795-8ff75a527d02
Who does still want to use an Outlook account?
- Wow. You were tortured, and then it was indeed a fix on the backend! Great job persevering! I envy your self-control.
Deleted thanks for the suggestion.
Posted here:
Start a new discussion in the space below, you can add a link to this discussion, of course it does not ensure success, but it is worth checking out!
Security, Compliance, and Identity - Microsoft Community Hub
The same issue is reported here:
https://learn.microsoft.com/en-us/answers/questions/1168272/oauth2-for-smtp-send-granting-accesstoken-but-retu
And here:
https://learn.microsoft.com/en-us/answers/questions/1168242/smtp-send-oauth-permission-not-working-for-consume
I have tried to chat with Microsoft support and they hang up three times with "Do you have any other questions?", which I think is insane.There is just no support for personal/consumer accounts and this is being proven again and again. My advice is not to use an Outlook/Hotmail/Live account for anything significant.
I assure you that this discussion is visible, so we can only wait for Microsoft to prepare a fix.
- There are plenty of people complaining here and at other places:
https://www.aqua-mail.com/forum/index.php?action=recent
The lack of a solution is completely due to Microsoft because they are the only ones who can resolve this. Like I said before, support for personal accounts is non existing.
