Ignition key failure

This is a 2002 Mercedes e320. Today I attempted to start the care as usual, but the key would not turn. I heard some sounds when I put the key into the lock, but just could not turn the key. The battery is fine. the parking brake is on and the transmission is in park. I tried both keys. Wat is the problem?

It may be in park, but it may not be fully in.  Try giggling the shifter a few times.

I tried that but got nothing.