"TNS:listener could not find available instance with given INSTANCE_ROLE"
*Cause: There are not any available and appropriate database instances
registered with the listener, that are part of the service identified by
SERVICE_NAME given in the connect descriptor and that have the specified
INSTANCE_ROLE (and INSTANCE_NAME, if specified).
*Action: Check to make sure that the INSTANCE_ROLE specified is correct.
Run "lsnrctl services" to ensure that the instance(s) have registered with
the listener and that they are ready to accept connections.