CNAME ineffective

For the sake of discussion, let’s say my MIAB runs on a server called I have custom DNS records for this starting with A 123.456.789.100

there’s also an MX record, and a bunch of CNAMEs mapping etc to

I have a CNAME for the www subdomain pointing to a different domain CNAME

This doesn’t work, and resolves to the A record for
I’ve added other subdomains with a similar result

I also manage a second domain from the same MIAB. Let’s call it CNAME

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.