Connecting CRM via SMTP error?

Question

Hello, I'm trying to connect an external CRM via my SMTP credentials but I'm receiving the following message and I'm unclear on what to do:

 

"{"code":"EAUTH","response":"535 5.7.139 Authentication unsuccessful, user is locked by your organization's security defaults policy. Contact your administrator. [CH3P220CA0029.NAMP220.PROD.OUTLOOK.COM 2025-02-28T19:13:40.828Z 08DD56E4409A61F2]","responseCode":535,"command":"AUTH LOGIN"}"

Answer 1

Hello @Raoul Hunt ,

Thank you for reaching out Microsoft Q&A.

I Understand you are trying to connect an external CRM via my SMTP credentials, but you are receiving the following error message: 535 5.7.139 Authentication unsuccessful, user is locked by your organization's security defaults policy. Contact your administrator.

I see you have enabled SMTP for the user from Admin portal and disabled the security defaults. But still facing the same error.

Please refer to the document below and follow the steps outlined to address the problem:

https://learn.microsoft.com/en-us/exchange/troubleshoot/email-delivery/fix-issues-with-printers-scanners-and-lob-applications-that-send-email-using-off#error-authentication-unsuccessful

1. Verify that SMTP is enabled for the user by running the PowerShell commands mentioned in the article.
2. Ensure that security defaults are indeed disabled.
3. Check if there are any conditional access policies that might be affecting the user.
4. Review the per-user MFA (Multi-Factor Authentication) settings for the affected user account. If it is enabled, disabled for the user.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

Please Accept the answer if the information helped you. This will help us and others in the community as well.