This seems to be one of two problems from a quick glance. The easy one is if the IP Address is no accessible from the IME desktop or server.
Second one should have been more obvious but when a Host isn’t in the allowed hosts its not allowed to even connect or ping. The result is the IME application giving you the same error as it doesn’t exist. Add your host or Network to the trusted hosts and try again to add this IPS to IME.