Smartthings hub can't discover device

Hi, hopefully someone can help. I just received my konnected 12 zone kit this week and am having trouble getting my smartthings hub to discover one of the devices. I was able to get one of them added, which makes me think it is not related to the router.

Both devices seemed to connect to my wifi correctly, and I can see them both in the attached devices list on my router.

Is there anything else I should try before I conclude that it is a hardware issue with the device? I saw a post saying to try flashing the wifi module and trying again, but I’m not sure how to do that.

Any help is appreciated. Thanks.

If you were able to discover one of the devices then there is no issue with the router. 

To flash the module follow these directions -

what does flashing mean/do.  Some of us are not computer geeks so dumbing it down could be helpful