I think your listener is tuned for the dedicated connection only.
ORA-12545: TNS:name lookup failure
Cause: The listener on the remote node cannot be contacted.
Verify that the ADDRESS in the tnsnames.ora file and the listener.ora file is correct.
Verify that the listener on the remote node has been started. Enter:
lsnrctl> status listener_name
listener_name is the name of the listener defined in the listener.ora file. It is not necessary to identify the listener if you are using the default listener, named LISTENER.
If the output indicates the listener is not running, try starting it with the command:
lsnrctl> start listener_name