It sounds like you're referring to an on-prem active directory issue.
Can you provide the docs that you're trying to follow?
I suggest posting your question against the active directory forums here : https://social.technet.microsoft.com/Forums/windowsserver/en-US/home?forum=winserverds
As these forums are meant for Azure AD related issues.
More information on the Cert SErvices DCOM access group can be found here : https://morgansimonsen.com/2012/01/24/an-overview-of-groups-used-by-active-directory-certificate-services/