Problems changing mx record

I have a domain with a lot of load, then i need to change mx record to other server.

I change mx record and mail record to new ip at dns manager in ispconfig, but server continues sending emails for this domain with local queue. If i check dns records with dig they are ok, with new (and correct) ip.

Code:

Dec  3 13:53:48 dl20 postfix/local[27070]: 2AE348AAD0: to=<[email protected]>, relay=local, delay=0.07, delays=0.04/0.01/0/0.01, dsn=5.1.1, status=bounced (unknown user: "bull")

Server must be dl31 not dl20. It runs last ispconfig version and debian Etch. Thanks in advance