emailgtw -535 5.7.3 Authentication unsuccessful

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

Facing issue with the latest version (2.91) of emailgtw as it does not connect to smtp server  and get "535 5.7.3 Authentication unsuccessful" in the logs 

It seems the probe is trying to connect using NTLM, despite having explicitly configured "enable_auth = noauth" in the probe

The connection test is working fine

When downgrading to emailgtw probe version 2.84 all is working fine again and the issue occurs when the probe version is upgraded to 2.91

Environment

probe :emailgtw 2.91

Exchange server version 15.1.2507.58 is part of Exchange Server 2016 CU23 Aug2025 SU 

 

Resolution

emailgtw-2.91-20251008.135347-21.zip (build number 270) is attached with this KB which has a fix for this issue 

This fix will be incuded in emailgtw 2.92 GA probe version whose release is tentatively by end of this quarter.