TNS-12522

Error: TNS-12522: TNS:listener could not find available instance with given INSTANCE_ROLE

Causa: 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).

Acción: Check to make sure that the specified INSTANCE_ROLE is correct. Run "lsnrctl services" to ensure that the instance(s) have registered with the listener and that they are ready to accept connections.