[warning] 'Player' moved wrongly?

Solution 1:

This warning is generated every time a player moved to a position or at a speed which the server thinks is impossible. This can happen spuriously, as the assumptions the server makes aren't quite the same as what you can actually do (the server doesn't analyze the player's exact inputs), or it can happen due to an attempted cheat, or due to the world changing as the player attempts to pass through it (e.g. player moves through a block the server knows about but the client hasn't seen yet due to latency).

Whenever this happens the server sends a message to the client resetting the player’s position to the last valid one (this can be noticed from that player’s perspective as a sudden shift).

Solution 2:

It usually means the player in question is flying, as the server is not expecting the movements flying creates.

Solution 3:

It means that, from the perspective of the server, someone did something that should be impossible.

This usually means flying or falling into the void.