Am not getting the domainNameLabel correct

Hope it's okay to post a general question here that is not really an issue, but more my lack of understanding on what is being expected. I'm following this post on the Dell site (https://community.emc.com/docs/DOC-80070) to prepare and run this template. The writer said that the value for the Domain Name Label parameter in the setup script must be used as the CN in the SSL certificate that is created. In his example he has this value as "CN=cseregistry.rack04.cloudapp.azs.mhclabs.com". So in my setup script (and in my certificate) I used the value of "csregistry.local.cloudapp.azurestack.external", as this seemed comparable for my Azure Stack SDK environment. But when I run the deploy script, the deployment fails, complaining that "The domain name label csregistry.local.cloudapp.azurestack.external is invalid. It must conform to the following regular expression:
^[a-z][a-z0-9-]{1,61}[a-z0-9]$." Obviously I am misunderstanding something. Can anyone set me straight on this?

Start with the setup script and deploy script referenced in the report, then compare their Domain Name Label handling with the linked Dell guidance. Document what value is expected for the parameter and how it relates to the SSL certificate CN; the issue is complete when the deployment requirement is unambiguous.

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