SMTP XOAUTH suddenly failing for Outlook personal with '535 5.7.3 Authentication unsuccessful'

[M1966B]

Authenticating with XOAUTH is suddenly failing with 535 5.7.3 Authentication unsuccessful for smtp.office365.com for personal accounts (Outlook/Hotmail/Live). It started with a few accounts, but it seems more, and more people are suffering from this.

To be clear: authentication worked fine before for the same account. It just stopped working, with the same OAuth refresh token, but only for the SMTP server, not for the IMAP server. Authenticating with an (app) password for the same account is a workaround for this issue, so it is probably not an account status problem.

Normally "535 5.7.3 Authentication unsuccessful" means that SMTP AUTH is disabled, but this is not possible for personal accounts, as far as I know.

Examples:

https://contact.faircode.eu/?product=fairemailsupport

https://www.aqua-mail.com/forum/index.php?action=recent

Can somebody please look into this, or contact an engineer at Microsoft?

[#2]

This is about the SMTP server for Outlook accounts and therefore not related to a specific operating system.

[#3]

Hi @Viv_V 

Please check this article:

Sent email in Outlook.com comes back "delivery failed" - Microsoft Support

[#4]

@M19B66 

Please at this point is a link to Microsoft support, I hope that they will develop this problem.

"

"

Still need help?

To get support in Outlook.com, click here or select Outlook.com help icon on the menu bar and enter your query. If the self-help doesn't solve your problem, scroll down to Still need "

[#5]

There is no way to contact Microsoft about personal accounts. Try it yourself, and you'll see.

Basically, there is no support for personal accounts. That's what they say too when you contact them in another way.

I tell everybody to not use a personal Outlook account for anything important because it can stop working at any time, and there will be no support at all. In fact, I am considering to hard code this message in my Android app.

[#6]

@M19B66 

Opt in to the Exchange Online endpoint for legacy TLS clients using SMTP AUTH | Microsoft Learn

Now it occurred to me?

[#7]

@A1 this is not related to the issue in any way. Also, this is for Enterprise accounts because you can't change server settings for personal accounts.

[#8]

@M19B66 

504 5.7.4 Unrecognized authentication type (with o365 licenced account and pdf-device-scanner) - Mic...

In this Microsoft Q&A space, you can ask technical questions - I think there is a chance for an answer that will be helpful.

[#9]

@A1 the Office 365 team already said that they do not support personal accounts.

[#10]

@M19B66 

[RESOLVED] Can't Connect to Outgoing Server Settings - - Microsoft Community

[#11]

That doesn't help if the old EWS protocol (commonly called "Exchange", which is pretty confusing because an Exchange server is not the same as this protocol), isn't supported. Moreover, Microsoft stopped supporting the EWS protocol in 2018 (informally there were no updates since 2016 anymore).

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.

[#12]

There are a million Members in the MTC - only we discuss, I am a little surprised by the lack of a solution

@M19B66 

[#13]

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.

[#14]

@M19B66 

I assure you that this discussion is visible, so we can only wait for Microsoft to prepare a fix.

[#15]

The same issue is reported here:

https://learn.microsoft.com/en-us/answers/questions/1168272/oauth2-for-smtp-send-granting-accesstoke...

And here:

https://learn.microsoft.com/en-us/answers/questions/1168242/smtp-send-oauth-permission-not-working-f...

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.

[#16]

@M19B66 

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

[#17]

@A1 thanks for the suggestion.

Posted here:

https://techcommunity.microsoft.com/t5/security-compliance-and-identity/smtp-xoauth-suddenly-failing...