Slow DNS Lookup with activated OVH Firewall

Hi, as soon I activate the ovh firewall (ALLOW: 22,25,80,143,443,587, 8080,8081, tcp, icmp, DENY: ipv4)
all programms / scripts which need to translate a domain name into an ip need about 4-5 seconds more.
For example: A simple ping on the console to google.com needs 5 seconds before the first package comes back. With deactivted ovh firewall it needs less than a second.

My system debian 9 with ispconfig 3.1. I also tried to set another dns server in etc/resolv.conf without success. Current settings are:
nameserver 127.0.0.1
nameserver 213.186.33.99
search ovh.net

I have no clue if I need to open another port (tried 53 tcp/udp without success). Or what else I can do to have fast dns translation with activated firewall.

Best Regards