535: 5.7.139 Authentification unsuccessful / SMTP Server in external application / *Entra*

Question

Hi,

I am trying to use an Office 365 User Mailbox as an outgoing server for our ERP Software.

I am using the following information for the server:

Host: smtp-mail.outlook.com

Port: 587

TLS with certificate

Username and Password are correct.

I am getting this error for all the User Mailboxes in our System:

535: 5.7.139 Authentification unsuccessful, user is locked by your organization's security defaults policy.

Now I believe the solution to my problem is the accepted answer in this thread:

https://learn.microsoft.com/en-us/answers/questions/512954/535-5-7-139-authentication-unsuccessful?page=1&orderby=Helpful&comment=answer-515074#newest-answer-comment

My problem is, we do not have access to Azure, only Microsoft Entra. How do I solve this problem with the Entra application?

Thank you in advance!

Answer 1

Hi,

Based on your description of the problem, you may have misunderstood Azure and Entra.

Actually, Microsoft renamed Azure Active Directory (Azure AD) to Microsoft Entra ID to communicate the multicloud, multiplatform functionality of the products, alleviate confusion with Windows Server Active Directory, and unify the Microsoft Entra product family. For detailed information, please see: New name for Azure Active Directory - Microsoft Entra | Microsoft Learn.

After my tests, you can sign in to the Azure portal as a Security administrator, Conditional Access administrator, or Global administrator, and no other Azure permissions are required. So you could test the suggestion in the thread with your Office 365 admin accounts.