C315 The key is activated but why can't i open the cave?

After Sun Guishan arrived, the three keys were activated at the same time.

A suction force came from the stone door, sucking in all three keys floating in the air and inserting them into the upper left corner and the lower two corners respectively.

However, even though the key was tightly sewn together, the cave's stone door still remained unmoved, unable to be opened