Plesk Onyx webserver and Domains?

[Monroe]

Hello everybody.

I have a Ubuntu 16.04 server running with Plesk Onyx. I have the problem, if I create a subdomain of my main domain, I always get the error (DNS_PROBE_FINISHED_NXDOMAIN). No matter what I can do or need to set. I have already checked the DNS templates but without resolving this problem  

Thanks in advance