Error while sending mails, is the issue is with ESA end need to clarify.

[bsrinu001]

Hi Team, 

Please, sugget we are getting delivery failre messages as below: 

DCID 241184384) Message 573258656 to XYZ@hannover-re.com delayed. Reason: 4.1.0 - Unknown
address error ('403', ['4.7.0 authentication failed']) [('from', 'Lisa Bartosiewicz <lisa.ABC@zurichna.com>')]

We see the DCID also gerarated but mails not delivering. 

[Libin Varghese]

Hi,

The delivery connection being created would indicate the ESA completed processing the email and attempted delivery to the destination server IP.

The error in this case suggests authentication failed, which would suggest the destination server expects us to authenticate with them. For exchange servers authentication is always recommended to be set as anonymous.

You could also check if this is a TLS delivery issue by running a packet capture for the remote IP the ESA is attempting delivery to.

Regards,

Libin Varghese