While adding a CNAME record, you may receive the following error:
You may not mix CNAME records with other records for the same name
You are receiving this error because a CNAME record is not allowed to coexist with any other data as per RFC1912 section 2.4.
If you are using cPanel and you are trying to add a CNAME record for the main domain (i.e. domain.com), you may receive the following error:
domain.com. already has a SOA record
Canonical Name (CNAME) records create an alias for another domain name, which DNS resolves. This is why you’re unable to mix CNAME records with other records.
If the other record is needed more than the CNAME record for your domain, the existing CNAME will need to be deleted before you’re able to create the needed record. You can delete the CNAME record at WHM >> DNS Zone Manager or the account’s cPanel >> Zone Editor.