I have a fresh install of Ubuntu 18 on a server. I setup a static IP with netplan using networkd as renderer. On my network, I have 4 DNS Server, here the netplan config file:

network:
    version: 2
    renderer: networkd
    ethernets:
        ens160:
            dhcp4: no
            addresses: [192.X.Y.34/24]
            gateway4: 192.X.Y.254
            nameservers:
                addresses: [192.X.Y.10,192.X.Y.11,A.B.C.10,A.B.C.11]

I add a A record for xxxx.yyyyyy.com (who pointed to A.B.C.21) on my DNS servers (It's local servers) When I run the command nslookup xxxx.yyyyyy.com, I got the following answer.

Server:         127.0.0.53
Address:        127.0.0.53#53

Non-authoritative answer:
Name:   xxxx.yyyyyy.com
Address: 192.X.Y.21

So why it's a Non-authoritative answer ? It's on the same network.
Should I add a search in the netplan config with the domain name ?

Btw when i run systemd-resolve --status, i got the good list of DNS Server

...
         DNS Servers: 192.X.Y.10
                      192.X.Y.11
                      A.B.C.10
                      A.B.C.11

I don't have Network Managerinstalled on the server.

If anyone have an idea to solve this problem :)

Thanks,