Hello. Like I said in the title, I have little skill in the game, especially in comms. I attempted to set up a network for a Duna mission (after realizing that I didn't have a powerful enough antenna), only for the probes not to connect. The first probe, a fuel depot, has a HG-5, and nothing else (communications wise). After I lost control and realized that this was not enough, I sent a relay satellite. It is orbiting the sun, both is apoapsis and periapsis at about the halfway point between Kerbin and Duna. The relay has an RA-15 antenna. When put in orbit, it didn't connect with the depot, so I sent another relay. Again, no connection. Did I do something wrong? Do probes just not connect? Any help will be appreciated. Thank you in advance.
Images
This is the fuel depot.
This is the relay.
This is the map, showing both relays, the depot, Kerbin and their relative positions.