Opening the native app in WKWebView

I seem to have problems opening the app in the page that says

“Download the app
Continue to the app”

… in an iOS app in a WKWebView.

This works OK in iPad/Safari.

When clicking “Download the app” there is an error message “Error. Unsupported URL”. Not sure if this is due to configuration of the WKWebView, it may be. When clicking “Continue to the app”, nothing happens. Maybe this is (also) a configuration issue?

FYI, looking for help, until I go to look further into this issue.

EDIT

I think it’s about apple-app-site-association file but didn’t yet get it to work…