There was a reason. It happens to all of us. Your ball simply wore out. Balls average about 2-3 rounds, not counting putting, and then are removed. Watch the meter in the lower right of the screen; it'll keep you informed of how much "life" is left in your current ball.
Kinda like real life, after multiple whacks of a golf ball it becomes more mushy, less controllable because of dimple wear and scratches, etc. Then we remove the ball from play. In this case WGT does it for you.