I have received the WeatherFlow Smart Home Weather Station today and can not get the air to be added to the hub but the sky did connect. I have tired the troubleshooting page holding the button until the green light flashes slowly, tried restarting the iPhone 7 and using a different iPhone, reinstalling the app, restarting the hub and replacing the battery what ever i do it will not pair i have been trying for two hours straight now. I am wondering if @anon84912554 or @WFmarketing could maybe shed some light on the issue. The only other thing I can think is that the sensor itself came out with a defect. If that is determined to be the case, what can be done about it?
try power cycling your hub and then add the air device
I found power cycling the hub after each operation was a way to reliably add my devices after a hard reset tonight