Oracle Database Discussions

I have recently installed Oracle 11g on a Windows 2008 server and am now trying to connect via the Oracle client on my local machine.

Here is how I've been using Net Configuration Assistant so far:

Listener Configuration
The name of my listener is LISTENER_PROXIMA (proxima is the name of the server). Does this need to be named something else? Something specific?
I'm using TCP to connect.
I'm using standard port 1521.

Naming Methods
Local Naming and Easy Connect Naming

Local Net Service Name
Service name is ADMI04 (checked this against the lsnrstl service status on the server and it's correct)
Using TCP
Using the hostname proxima.domain-name.com
I'm attempting to connect as SYS (but have tried others with the same result)

When I go to test the connection I keep getting the ORA-12514 error. Does anyone know what I should do? Reinstall the listener? If so, are there any suggestions or guidance for that?

Thank you.