I've bought a secondhand Instinct Solar 2S. I plugged it into my desktop and it's recognised on Garmin Express. But it will not pair with my Iphone. So far I have reset the watch, restarted the phone, restarted the watch (about a dozen times), deleted Garmin Connect twice and restarted that too. Each time, the phone finds my device, but then I just get a message that pairing has failed. I never see a pairing code. Beyond all the resetting and restarting, what else can I do? Iphone 16 iOS 18.5.