Delivery Status Notification (Failure)

From: IronPort@mx-cluster18.immenzaces.com
Domain: IP info mx-cluster18.immenzaces.com
MX-server: IP info mail.ticketnew.com
Size: 192 Bytes
Create: 2024-06-18
Update: 2024-06-19
Score: 0
Safe: Yes

The following message to was undeliverable. The reason for the problem: 5.1.0 - Unknown address error 550-'5.1.1 User unknown; rejecting'