We are currently setting up the Finance Module in SIMS. As part of the process, we need to configure email using OAuth authentication with Microsoft 365.
One of the required steps is to register an application in Microsoft Entra ID (formerly Azure AD). The documentation provided by ESS (SIMS) is not particularly helpful, but after a number of attempts we managed to complete the setup.
Authentication is successful; however, when we click "Test Email", we receive the following error:
535 5.7.3 Authentication unsuccessful
I raised a ticket with ESS and spent over an hour on a remote support session with them. Their conclusion was that I need to log a support ticket with Microsoft.
I have done so, although I am not convinced this is a Microsoft issue, as we have several other app registrations used for email workflows that are working perfectly well.
Microsoft's documentation links error 535 5.7.3 to the following possible causes:
SMTP authentication not enabled
MFA-related authentication issues
Azure/Entra security or Conditional Access policies
I have ruled out all of the above.
Has anyone using the SIMS Finance Module with OAuth authentication come across a similar issue?
Changes made: Improved grammar, punctuation, sentence structure, and flow while keeping the technical details and meaning unchanged. The tone is now clearer and more professional for posting on a support forum or sending to ESS.