I wanted to reply in the other thread, but is closed now.
I downloaded the most recent PKHeX, but still not working. The QR code seems incompatible (it what the 3DS says when I try to scan)
As I said earlier, the firmware is 9.5.0-22E (old 3DS), the injection through browser should work. As you can see the QR format is different from olders version of PKHeX