I was working on a vending machine that utilized the /scoreboard command and I was entering a command that would subtract money from what you inserted. The whole thing was going well when I entered the command: /scoreboard players remove @a[score_v_min=1] v 1. I expected this to subtract one point from the Vending machine score, but instead it caused the server to refuse connections, showing the error message: Internal Exception: io.netty.handler.codec.DecoderException: java.io.IOException: The received string length is longer than maximum allowed (20 > 16).

To make this happen:
1. Log on to a server that uses MCProHosting.
2. Give yourself a command block
3. Type in your chat "/scoreboard objectives add v dummy VendingMachine" and then "/scoreboard objectives setdisplay sidebar v"
4. Type in the chat "/scoreboard players add [whatever your player name is] v 10"
5. Place the command block down and enter the command "/scoreboard players remove @a[score_v_min=1] v 1"
6. Activate the command block. This will crash the server.