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

[M19B66]

Please see here for the details:

https://techcommunity.microsoft.com/t5/outlook/smtp-xoauth-suddenly-failing-for-outlook-personal-wit...

Note that this is about personal accounts for which SMTP AUTH cannot be disabled, and that this worked fine for existing setups/configuration until the end of January.

In other words, this is not something which can be resolved by changing configurations or software, and therefore is rather likely a problem with the Outlook SMTP server.

[#2]

I also confirmed that until now it is not working.

535 5.7.3 Authentication unsuccessful [SJ0PR13CA0189.namprd13.prod.outlook.com 2023-04-14T01:41:59.958Z 08DB3BD5C46109BA]

I am using offline_access and SMTP.Send as scope via Device Code Flow
These are the endpoints that I used to get exchange device code for an access token to be able to send email using consumer accounts using oauth2

device_endpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/devicecode",
token_endpoint = "https://login.microsoftonline.com/common/oauth2/v2.0/token"

[#3]

@M19B66 

Any luck with a resolution on this?  

[#4]

It seems like Microsoft have quietly resolved this issue, it has suddenly started working for us. https://learn.microsoft.com/en-us/answers/questions/1168242/smtp-send-oauth-permission-not-working-f...

[#5]

Yes, it seems there was a mystery fix happened on MS side. 🙂
Anyway, due to this issue I was able to produce a Test Tool written in Rust Programming Language just to test this workflow. https://github.com/LorenzoLeonardo/microsoft-smtp-xoauth2-test-tool

[#6]

@Enzo_Tech Is this issue fixed now i tried testing SMTP Xoauth with my outlook personal account. Iam getting the same error. If it is fixed can you help me the solution?

[#7]

@venkat285 

Hello yes it is now working please check the scope used under providers in my sample test tool written in Rust Programming language https://github.com/LorenzoLeonardo/smtp-xoauth2-test-tool