Some of this depends on what kind of garage door opener you have .. whether the wall pushbutton is a simple momentary contact button, or if there more electronics involved. If a Chamberain opener, what color is the learn button?
Take it one step at a time. You have a relay on the ZEN17 wired in parallel to the wall button, correct? If you close that relay on the ZEN17 for one second and then open, does the door operate?
That's good. Now it is just a software task. You don't say what app you were trying, but if it is a community app he learned of here, follow up in that app's thread.
You could also just follow the instructions at the link below, and reach out to Zooz if needed.
Alternatively, you could probably do what you want with RM without having an app at all.
Would need some details about your contact sensor, the driver it has must not have the correct capabilities to show in that list. So what is the contact sensor and what driver is it using (listed as TYPE on the device page).
is it connected to the Zen17 or connected to HE in some other method.
if it is connected to the Zen17 has the input been configured as a contact sensor. I believe this may be one of the options you have to unpair and repair after setting the input to the new mode.
When you look at the Zen17 device in HE do you see something like this. My image has input 2 set to a contact sensor, but my point is you should see a child device as a contact sensor.
I have been using this with no problems. On my Genie if I connected a contact such as the ZEN17, it interfered with the wall push button unit. Thus had to go the Aladdin route.
You will likely need to repair the device to get the contact sensor functionality to fully kick in. but then it should show up on that list to be selected.