Mail delivery failed: returning message to sender

Good Morning I have a dedicated server with CENTOS 7.9 and Cpanel/WHM v94.0.3 and when trying to send an email I receive the following bounce: 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: xxxxx@xxxxx.xx host mail1.bravehost.com [65.39.211.20] SMTP error from remote mail server after RCPT TO:: 550 5.1.1 : Recipient address rejected: User unknown in virtual mailbox table Reporting-MTA: dns; xxx.myserver.xxx Action: failed Final-Recipient: rfc822;xxxxx@xxxxx.xx Status: 5.0.0 Remote-MTA: dns; mail1.bravehost.com Diagnostic-Code: smtp; 550 5.1.1 : Recipient address rejected: User unknown in virtual mailbox table