ok I edited /etc/hostname to server.wzk.cz then run hostname -F /etc/hostname and restarted postfix and amavis.
Then i restart amavis, says:
admin@server:~$ sudo /etc/init.d/amavis restart
Stopping amavisd: amavisd-new.
Starting amavisd: head: „/etc/mailname“ can't open for read: No such file or directory
Is this error or only warning?