Mail delivery failed: returning message to sender

From: Mailer-Daemon@ispgateway.de
Domain: IP info ispgateway.de
MX-server: IP info bounceout05.ispgateway.de
Size: 483 Bytes
Create: 2025-01-29
Update: 2025-01-29
Score: 0
Safe: Yes

This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: hgweber58@t-online.de (ultimately generated from briefkasten@krankengymnastik-weber.de) host mx02.t-online.de [194.25.134.9] SMTP error from remote mail server after RCPT TO:: 550-5.1.1 user unknown 550 5.1.1 Unknown recipient.