Problem:
You are using CPANEL with a third party slave DNS, and you see in your /var/log/message that external zone transfer are denied.
Oct 19 13:05:08 your_server_name named[18147]: client slave_DNS_IP#59149 (your_web_site): view external: zone transfer ‘your_web_site/AXFR/IN’ denied
Solution:
Edit /etc/named.conf, and replace
allow-transfer { “NONE”; };
with
allow-transfer { slave_DNS_IP; };
Then reboot your DNS server with service named restart and you should be ready to go !