SASL authentication failed

Question

Hi,

I'm trying to configure postfix with office365,  but it gives me this error and I don't get authentication

Can you please help me?

Thanks,

Ana.

Answer 1

Hello Ana,

Thanks for your post in Microsoft community. According to your post, we understand that you have configure SMTP relay to send emails from your application/software and had set up with SMTP client submission. For SMTP client submission method, O365 user account is required, so we would like to suggest you to check if you can login with the same credentials of that account on another device or Outlook web app. Check port settings are set as 587 or 25 and make sure TLS is enable at your application/software end.

You may refer this below article:

• How to set up a multifunction device or application to send email using Office 365: https://support.office.com/en-us/article/How-to-set-up-a-multifunction-device-or-application-to-send-email-using-Office-365-69f58e99-c550-4274-ad18-c805d654b4c4?ui=en-US&rs=en-US&ad=US

 If we misunderstand your concern , we request you to kindly provide brief information about your requirement, so we can check further.

Thanks and regards,

Ankita Vaidya

Answer 2

Hello Ana,

We haven’t hear back from you. If you would like further assistance, please provide us with the information above at your convenience.

Thanks and regards,

Ankita Vaidya

Answer 3

Hello Ana,

Thanks for update. To narrow down the issue, could you please kindly provide below information via private message?

• The screenshots about how you set up SMTP(client submission).
• Is your account managed in pure cloud, On-Premises or hybrid?
• The screenshot of the complete error message and if it will generate any SMTP log, please upload the entire log for further check.

For your privacy, we will send you private message for collecting it.

Thanks and regards,

Ankita Vaidya

Answer 4

Hello Ankita,

I have already tried everything you comment, and I also read this article, but I can't find the solution to get authentication.

I have also followed several tutorials that I have found:

 https://www.informaticapressapochista.com/linux/configure-postfix-use-office365-smtp-relay-ubuntu-16-04/

 http://kb.sites.apiit.edu.my/knowledge-base/how-to-configure-postfix-relay-to-office365-on-ubuntu/

 https://www.heelpbook.net/2019/postfix-smtp-e-mail-relay-for-office-365/

but without success...

Trying to configure postfix with gmail, it works correctly, I don't understand why it fails with O365.

Thanks,

Ana.