Oracle Database Discussions

I have installed toad full (client + server). we dont have oracle home in the machine. Third party is having the database and we connect to them by the hostname and the service name. I am able login to sql Developer using the hostname and the database. But I am unable to login into toad by just using the direct connection.
and it is giving an error called client not installed. so can we directly connect to the database using the toad?