Recently my Pixel started showing the following message:
Development Mode Active -
URLs will be routed to Dev Manager in order to
Unfortunately Instant Apps is not yet available in India. That means, Instant Apps features are by default turned off on the real devices, including in development environment. See the list of supported countries here: https://support.google.com/googleplay/android-developer/answer/7381861#production
We are working on this issue and will provide an update in a few weeks. In the mean time, please use emulators for you development.
Now Instant apps is available in India. You can check by searching buzzfeed tasty in chrome. Attaching screenshot below
Or you could visit https://developer.android.com/topic/instant-apps/index.html and click the screenshot on that site. Post clicking website will open. Below that website a popup will show to "open app". Post clicking "open app", instant app will get opened
Note : Turn on instant app in Google menu in Settings in phone before trying above
In your instant App run configuration. Try To enable Instant APP Provision and "Clear Provisioned Devices Cache"