User unknown in virtual mailbox table

I created a new email account (simhof@rosinto.com) on server #1 tonight and I tested inbound to the new email account on server #1  from Server #2.  I get the following error (from tbird and roundcube) when attempting to send to the new email account (simhof@rosinto.com) from server #2.  But interestingly, email from server #1 to server #1 works properly as local email.  I tried tbird and roundcube both and got the same error.

An error occurred while sending mail. The mail server responded:
550 5.1.1 <simhof@rosinto.com>: Recipient address rejected: User unknown in virtual mailbox table.
Please check the message recipient "simhof@rosinto.com" and try again.

This is only happening to new email accounts on the server #1.  Previously created email accounts on server #1 work fine.

Ok.  This problem has something to do with forwarding.  New email accounts on server #1 work fine on other domain.  The problem is rosinto.com.

Last night I tried to create a forwarding of simhof@rosinto.com.  then I deleted the forwarding rule in control panel.  After that, nothing works with rosinto.com inbound email.

So. THIS IS EMAIL FORWARDING PROBLEM.

check the ip if it is reachable  this is not CWP issue.