For the sake of discussion, let’s say my MIAB runs on a server called box.example.com. I have custom DNS records for this starting with
box.example.com A 123.456.789.100
there’s also an MX record, and a bunch of CNAMEs mapping ns1.example.com etc to box.example.com.
I have a CNAME for the www subdomain pointing to a different domain
www.example.com CNAME otherdomain.com.
This doesn’t work, and www.example.com resolves to the A record for box.example.com
I’ve added other subdomains with a similar result
I also manage a second domain from the same MIAB. Let’s call it example2.com
www.example2.com CNAME otherdomain.com.
works fine and I can see the cname record with dig.
I’ve had this setup working before, and I can’t see the difference with what I’m doing now. I haven’t forgotten to end the names with dots. There’s only one record for each of the subdomains in question.
Problem #1. NS records must be A records not CNAME records. The same is true of MX records, though MX records will work.
Not sure why the problem there …
Will you PM me your domain name? A second pair of eyes may solve this.
Who is your DNS provider / registrar? GoDaddy as an example has a specific place to configure nameservers used for a domain.