Undelivered mail

[Boter]

I have a domain, which is manager by google apps (mail), but I have the pages available on the net through ispCP. I want somehow delete domain from mail system, because mail is not delivered.. See the error




Jan 11 02:25:43 snowflake postfix/virtual[10010]: 8821725E32D: to=<mitja@*.net>, orig_to=<info@*.si>, relay=virtual, delay=0.04, delays=0.02/0.01/0/0.01, dsn=5.1.1, status=bounced (unknown user: "mitja@*.net")

Any idea?