Friend cannot Connect to our rented dedicated server from Host Havoc

My friend rented a server through Host Havoc, and we all can connect to it except his girl friend whom he lives with. The server never registers that she’s trying to log in, and she receives an error “connection failed x amount of times” i’ve been given the task of managing the server because i have the most experience, but i have no idea what to do in this situation. Can Someone PLEASE help me