I can not conect from sql developer to a server

Question

Hi,

 

I´m running sql developer from a client to connect to a server but i  got this error:

 

Estado: Fallo:Fallo de la prueba: Error de E/S: The Network Adapter could not establish the connection

 

I´m using tnsnames.ora not listener.ora

 

Some help?

 

Thank u