RMS - Rights Management subscription is missing

Hi,

I have Azure Subscription, I want to activate RMS subscription on my Current Subscription, however when I select active directory and click on Active am not getting option to subscribe to RMS, it just displaying warning message of RMS subscription not available.

I have used this https://docs.microsoft.com/en-us/rights-management/deploy-use/activate-azure-classic as reference.

is RMS is not available to Azure Classic?

Thanks,

Chala.