Your question is Subscription Revenue Mystery. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You have a subscription service and your monthly users are increasing but revenue stays the same. What could be the cause? Explain how you would define the relevant user and revenue metrics, decompose the relationship between them, and prioritize your investigation. Discuss the data you would request, how you would distinguish a mix shift from a measurement issue, and which actions or experiments you would recommend after identifying the cause.