Which metric provides the most immediate indication of a sudden server issue impacting player experience?

Concurrent Users (CCU) provides the most immediate indication of a sudden server issue. Concurrent Users represents the number of players actively in an experience at any given moment. A significant and rapid drop in CCU is a direct indicator that players are disconnecting, which could be due to a server crash, lag spikes, or other technical problems affecting the game's stability. While other metrics like Daily Active Users (DAU) and Monthly Active Users (MAU) offer insights into broader trends, they are lagging indicators, meaning they reflect past activity. Session Length could indicate issues over time, but doesn't provide the immediate, real-time feedback that CCU does when a server problem emerges. A sudden, sharp decline in CCU directly correlates to players leaving the experience en masse, signalling an immediate problem that needs investigation. For example, if your game usually has 1000 CCU and it suddenly drops to 100, it's a strong sign of a server issue affecting the player experience.