emailgtw error authenticating to Office365 smtp server error 535
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emailgtw error authenticating to Office365 smtp server error 535


Article ID: 7817


Updated On:


DX Unified Infrastructure Management (Nimsoft / UIM) CA Unified Infrastructure Management On-Premise (Nimsoft / UIM) CA Unified Infrastructure Management SaaS (Nimsoft / UIM)


Unable to configure the emailgtw probe settings using an Office365 SMTP server.

"Test" option in emailgtw probe SMTP menu fails and produces the following error in the emailgtw.log:

emailgtw: EHLO
emailgtw: 250-%<server> Hello []
emailgtw: 250-SIZE 157286400
emailgtw: 250-PIPELINING
emailgtw: 250-DSN
emailgtw: 250-AUTH LOGIN XOAUTH2
emailgtw: 250-8BITMIME
emailgtw: 250-BINARYMIME
emailgtw: 250 CHUNKING
emailgtw: (cmd_test_smtp_login) smtp_open succeeded
emailgtw: AUTH LOGIN
emailgtw: 334 VXNlcm5hbWU6
emailgtw: (test_login) getting username and password for host]
emailgtw: xxxxxxx - found match []
emailgtw: <suppressed>
emailgtw: 334 UGFzc3dvcmW6
emailgtw: <suppressed>
emailgtw: 535 5.7.3 Authentication unsuccessful [%<server>.<domain>]


  • emailgtw probe version 2.83
  • Office365 SMTP server


  • This issue is associated with the authentication process to the Office365 managed by the Office365 Admin.


Here are some helpful links to troubleshoot this problem:

 1. Use Telnet to verify SMTP communication outside of the emailgtw probe

How to Use Telnet to Test SMTP Communication

 2. See the following link with a solution for the "535 5.7.3" SMTP error: