I suggest you use another source, do not waste time with this ... It is a very stable source, but the public version has many problems and can be a good time wasted ...
The function to know whether or not the player is online is this one. Search the source for examples
Code:
public static Player GetUser(string name)
{
if (string.IsNullOrEmpty(name)) return null;
name = name.ToLower();
return Players.Values.FirstOrDefault(user => user.Character.Name.ToLower() == name);
}
If it returns null, is because it is not online ... '-'