Apple TV+ on MacBook Air not playing anything

I am unable to open any TV shows or films through the Apple TV app on my MacBook Air. "This system cannot play this protected movie."

This despite:

• I have subscribed to Apple TV+
• I have ensured that my MacBook is authorized on the Apple TV app (Account > Authorizations > Authorize this computer)
• I can watch shows through the Apple TV app on my phone, and can broadcast these onto my computer using AirPlay (in addition to being annoying, I can't do anything else on my computer while in this mode).

I am at a loss and thinking I should cancel my subscription as I don't want to be watching shows on my phone. I'd be really grateful if someone could help!