DNSCrypt usage problem

I am following instructions from Alternative DNS Resolver - Whonix

after installing libsodium and dnscrypt, i run it and get error:

sudo dnscrypt-proxy --tcp-only -R cypherpunk
[NOTICE] Starting dnscrypt-proxy 1.4.3
[INFO] Initializing libsodium for optimal performance
[INFO] Generating a new key pair
[INFO] Done
[ERROR] Unable to bind (UDP) [Address already in use]

how to fix?