When you are connected to VIN, also connect via USB so you can send terminal commands and see what is happening. Be careful when connecting via USB while also connecting via VIN though to avoid USB ground loops. Use a laptop on battery power to be safe, or at least ensure that the PC and printer are on the same outlet.
From the terminal send M552 and see what it responds with.
Cycle through the network commands and see what it says for each.
M552 S-1
M552 S0
M552 S1
M587