powerline to detached garage

I just bought 2 AV200's for the same purpose in a similar config. Our power feed goes into the house's breaker box, then there's a subfeed that heads out to the garage. wire feet is ~20 from the first AV200 to the house panel, <75ft from house panel to garage panel, and 25 or so to the garage door opener plug where the other AV200 is. i can't get any connection. There's no surge protection of any kind in line. Admittedly, all I've done so far is hook them up in adjacent rooms back in the house to verify they work, but I don't have a lot of flexibility on where in the garage they go. Going to also try swapping the garage outlet to another breaker on the other leg of the 220v main feed to maybe help things a little.