This forum is for people who are using the Samsung smartthings home automation platform. So all of the answers that you will get will be within the context of that platform.
It’s a very active forum, so it does tend to come up near the top in general google home automation searches, but it is specific to the Samsung platform.
Since you aren’t using that, your best bet is to check with Amazon support. They’re generally very good about this kind of stuff if you bought the product from them. Use the “contact us“ button on the left side of the screen:
One common problem that does come up with these devices is that your phone that has the device app will have to be on the same network as the device when you set it up. A lot of android phones automatically switch to the 5.0 network even if you select the 2.4, so that might be the problem.