Will state I do not have a solid idea up front, but a couple thoughts/questions.
1) You mention a few phones, were they all iPhones, or did you try an android? I ask because if it will not work with either phone type, that steers towards a cable/usb issue very quickly. It could easily be a bad connection os the USB cable to the main unit or similar if neither phone types work. I understand that you can't use a USB drive or similar with BRP Connect, so might be worth trying an android.
2) Were the phones UNLOCKED when you plugged them in, and BRP Connect installed. The sequence I had to use the first time was a) let radio boot up, b) unlock phone c) start BRP Connect app on phone, d) plug phone into USB, d) the phone screen would go to a BRP page and be locked for direct input.....things worked from Spyder controls from there. Also, were the phones in cases? If so, some cases lock phones when shut so the case must be open for BRP connect to work. Phone unlocked is KEY before plugging in!
3) Have you tried uninstalling and reinstalling the BRP Connect App. This is unlikely to be cause, since you use multiple phones, but the app requires several permissions to the phone.
4) I assume the phone is newer, make sure version go IoS is compatible.
5) What version of software is your bike running? (Can check through menus). If not at least 13.2, connections issues were prevalent. 13.2 seems to connect pretty well and reliably, my experience, but my 2018 cane with 1.X and was TERRIBLE. If you are older/lower than 13.2, the current version is 20.8.
Very possibly a USB issue, but wanted to throw out a few things to try in case. Just ideas, no magic bullets. Good luck
