Turn left and learn the rules.
Which of the following is a valid unique identification for a referee?
Referees do not need to wear any identification on their back
Only a number, which must be between 1 and 4 alpha-numeric digits
Only a number, which may contain letters and symbols
Only a number, which must be between 1 and 4 numerical digits (no letters or symbols)Could not connect : The server requested authentication method unknown to the client