Failed to enroll a mac

Symptoms

After the enrollment process attempt the Parallels Mac Management Agent shows one of the following errors:

• The Parallels Mac Management for Microsoft SCCM registration was unsuccessful. Please contact your system administrator for assistance. License status: Expired
• The Parallels Mac Management for Microsoft SCCM registration was unsuccessful. Please contact your system administrator for assistance. License status: Not Activated

At the same time, the System Center Configuration Manager Console > Administration > Overview > Parallels Mac Management > Licenses pane indicates that the license is active, valid and has enough available seats to connect additional Macs.

The /Library/Logs/pma_agent.log has the corresponding record on the Mac, i.e. for the "Not Activated" state:

pma_agent_registrator failed: License status: Not activated (-1)

Cause

A record of another, currently unlicensed Parallels Configuration Proxy (CM Proxy), is present in the same domain.
As a result, a Mac is routed to a wrong CM Proxy with the expired license key.

Resolution

Delete the obsolete/unlicensed PmaConfigMgrProxy items in ADSI Edit (adsiedit.msc) > System > ParallelsServices, leaving only the active ones.

Please note that additional permissions to manage the Domain Controller might be required.