If you migrated all accounts from old server to new server with different IPs then you have to change DNS records with new IPs for all domains. Please use following step to replace the IPs on new server.
#cd /var/named/
#replace “1.2.3.4” “11.12.13.14” — *
1.2.3.4 is old IP and 11.12.13.14 is new IP
I hope it will help you. 🙂