DNS manager not starting

Hello,
I need to create custom nameservers
I installed DNS manager and added domain .. but service won't start

SleepyFoX
please execute netstat -ntulp and show me the result

i think there are other nameserver running on your server

I can't run this way, I'm using a vps ubuntu 20.04

aaP_jouned12
Hello, is there an error during startup?
systemctl restart pdns