How to troubleshoot deep-linking issues in a custom app using Buy SDK?

[Alex_Iachimov]

Hello Shopify Team.
I'm trying to add deep-linking to the custom app that is using Shopify Buy SDK.
I followed the steps mentioned in iOS and Android SDKs documentation:
Android - https://shopify.dev/docs/custom-storefronts/additional-sdks/android#step-3-set-up-android-app-links
iOS - https://shopify.dev/docs/custom-storefronts/additional-sdks/ios#set-up-universal-links 
But unfortunately it's not working and it's hard to understand why.

I'm pretty sure that I'm using correct package ID and  SHA256 fingerprint to configure Android part and correct bundle ID for iOS part?

Could you please advise what could be wrong?