Smartthings and iTach IP2IR Example Code?

This is probably too obvious, but have you authorized echo to use that specific button?

Whenever you add a new device, you have to individually authorize it before echo can use it.

See step 10 in the following:

If you did that already, open up the Alexa app and see if the button shows up in your list of devices, and if so what device class it is. It’s also possible that you used a device class that echo doesn’t know what to do with.