I’ve just installed a BT600 homespot with 2 slave units. It works fine with a pc, an Apple TV and 2 iPhones - an old iPhone 5, and a newish iPhone SE. However, my own iPhone 6s won’t connect to either homespot, although it connects to the BT hub6. Presumably my settings need to be adjusted.
Its possible that the iPhone does not consider the wireless encryption secure enough. There may be an option on the phone to connect to less secure networks. I am sure this issue has been mentioned before.