How I mappead a domain that dns server is in same ip?


I have a wordpress network in a VPN. In this same server is the DNS server that resolves the address of the site that I want to map, ie there is only one A entry that points to the ip of the server. The ip is shared with other domains.
I checked the propagation of the domain and it is ok.

But I am unable to map the subdomain to my network. There is a problem in the server configuration?

I can´t redirect the domain to network root. This is the error msg:

A DNS entry for “” already exists. You must remove this DNS entry from all servers in the DNS cluster to proceed.

Thank you,