Sky mini box not connecting to main Q box

[Bazzer1947]

I have four Mini Q boxes, all four used to connect, now one of them cannot connect to the main sky box. I have tried several times ro reconnect but failed. Could it be out of range, although it did work without any issues. I also have a sky booster; does this just boost the wifi signal. When connecting to the main box how does this work, is is a wifi signal from the main box