How to correctly use deeplinks?

I wish that a third-party app was able to open my app using Deeplinks.
I’m passing to this third-party app the url_scheme to open: myapp://

My app is an Ionic4 app with Cordova plugins and this plugin to manage Deeplinks.

The problem is that, when the redirect should take place, nothing happens.

I’ve defined the Deeplink routing in this way:

import { Deeplinks } from '@ionic-native/deeplinks/ngx';

constructor(private deeplinks: Deeplinks) { }

    '/payments': {'payments': true}
   }).subscribe(match => {
     console.log('Successfully matched route', match);
   }, nomatch => {
     alert(JSON.stringify(nomatch ));
     console.error('Got a deeplink that didn\'t match', nomatch);

If I open a web page from the mobile with this content and I click on the link:

  <a href="myapp://">CLICK ME</a>

My Ionic app opens correctly.
From the third-party app, my app doesn’t open.

So the question is, am I missing some steps in setting up Deeplinks?
Should I do something on the domain “” ?

Thank you very much