Regex to restrict certain usernames?

Can someone help me with some functions ?
We trying to make plugin, that restrict players to connect to the server with restricted characters, but we can`t find the function for this.
Trying to use this function, but didn`t work

Code:

void OnPlayerConnected(PlayerIdentity identity, uLink.NetworkPlayer player)
        {
            string Name = identity.Name;
            string country = "CmeniNick";
            bool reg = Regex.IsMatch(Name, @"^([a-zA-Z0-9-+_\.\s\]\[]{2,16})+$");
            if (reg)
            {
kick
            }
        }