[Custom SMTP Email Server] - Outlook365 Error - 535 5.7.139 Authentication unsuccessful, the request did not meet the criteria to be authenticated successfully.
As of 2024, If you're using Outlook365 as your SMTP server, you might encounter the following error when sending emails:
- 535 5.7.139 the user credentials were incorrect
- 535 5.7.139 Authentication unsuccessful, the request did not meet the criteria to be authenticated successfully. Contact your administrator.
- 535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant. Visit https://aka.ms/smtp_auth_disabled for more information.
Commentary: Microsoft no longer supports Basic Authentication, and it has disabled SMTP AUTH in all tenants in which it's not being used. This is done to force customers to move from apps that use basic authentication to Modern authentication[OAuth 2.0]. Check Microsoft's Deprecation of Basic Authentication Documentation for more details.
Since SMTP AUTH has been disabled, 535 5.7.139 Authentication unsuccessful error will come up, even when proper credentials are used.
As of summer 2024, Sisense doesn’t support Modern Authentication(OAuth) for SMPT. To continue using Microsoft Outlook with Sisense you need to use Legacy Authentication.
Additional Resources:
https://docs.sisense.com/main/SisenseLinux/custom-email-servers.htm
