Hi - when you enable autoenrollment on a certificate it uses information from the source object to populate the certificate. In this case, can you validate that the DNS name exists on the Active Directory account that corresponds to the machine?
I would use an editor/viewer that allows you to see the attributes on the AD computer object to see if they are set properly. Typical tools include: ADExplorer, ADSIEdit, LDP, Active Directory Users and Computers (Windows Server 2008+).
~fr3dd