Each phone can different variant /model numbers, it might be that particular variant is not supported yet, you might have to check the support devices list and the supported variant model number list.
I made sure I got one that was on the supported list :)
- Samsung Galaxy Note 5 (SM-N920I)
It's all setup correctly, but when I go to use it, it fails and then I have to swipe/insert card.
Whenever I buy something I record it in YNAB (you need a budget), so paying via phone is handy since I can easily enter the cost then. Originally thought it would be gimmicky but I actually really love paying with phone, its become my preferred payment method.