Warner Media Group owns a bunch of different services, including HBO and Cinemax. Might you not be recognizing this as being for a subscription you do have?
List of Warner Media Group brands: https://www.warnermedia.com/us/brands
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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