Postfix issue after server migration

[soap]

hello, i hope someone can help me.

i m trying now since days to resolve this issue:

i have this errors in my mail.log

Jun 26 13:02:09 64158 postfix/qmgr[1440]: 6270279C2EE2: from=<root@old.domain.com>, size=928, nrcpt=1 (queue active)
Jun 26 13:02:09 64158 postfix/qmgr[1440]: 6EA1882C368B: from=<root@old.domain.com>, size=928, nrcpt=1 (queue active)
Jun 26 13:02:09 64158 postfix/error[2226]: D2B7472C36C9: to=<root@old.domain.com>, relay=none, delay=239371, delays=239371/0.11/0/0, dsn=4.0.0, status=deferred (delivery temporarily suspended: mail for old.domain.com loops back to myself)
Jun 26 13:02:09 64158 postfix/error[2226]: warning: defer_append: ignoring dsn code "5.4.6"
Jun 26 13:02:09 64158 postfix/error[2226]: D7B1932C3698: to=<root@old.domain.com>, relay=none, delay=256507, delays=256507/0.11/0/0, dsn=4.0.0, status=deferred (delivery temporarily suspended: mail for old.domain.com loops back to myself)

BUT

my new host domain ist new.domain.com ( old. domain.com dont exists anymore, server is down and DNS record removed)

i checked main.cf and master.cf and there is the actual hostname in it.

i used dpkg-reconfigure postfix without configuration and the problem is still there.

i have the old hostname in my mail.log still there.

sending and reveiving mail works fine.

i m using amavis and clamav and everything works good.

How can i fix that? Thank you