Missing AppLink Url, however android link of game is already added , Unable to send request

I am inviting one of my friend via Fb.Mobile.AppInvite to my game (which is build on Unity and published on Android ). As facebook Api suggest to insert first argument of this method as a Applink, I have put the android link of my project but still it gives the error of missing App link url. I have seen is Facebook example and documentation that they use applink of this type “Https://fb/me/***********”. I have visited the stackover flow and they provide me the wayout of creating the applink whose link is not working or removed by facebook team.

However the documentation facebook provides is for Android or iOS . Its not for Unity.

The Facebook SDK for Unity also changes like the native iOS and Android SDK. Please be noted that Facebook don’t really remove or deprecate the function usually on the SDK for Unity as it’s just a wrapper for the native code.
What Facebook does is keep the function arguments as it is for new versions, but they aren’t doing anything. Applink wouldn’t show a picture any more.

see more here
https://stackoverflow.com/questions/40781149/app-link-not-working-for-facebook-on-android
https://stackoverflow.com/questions/39539695/facebook-app-linksdeep-links-not-working-on-mobile-browsers

https://stackoverflow.com/questions/35350150/facebook-deep-linking-app-link-not-working-on-ios

https://stackoverflow.com/questions/30333567/why-this-deep-link-applink-generated-by-facebook-does-not-work