My colleague created a new embedded Canvas app and I went to check it the model-driven app’s form. However, all I could see – just the error message.
As obvious as it could be: you need to share your app with users if you want them to use it in Dynamics.
So go to the PowerApps editor (https://web.powerapps.com/environments), select your app to share. Enter a name, email address or Everyone…
If you choose Everyone, you will have the opportunity to share the app with all users in your organisation.
Probably, in my case, this would be a good option.
Also you could add Everyone and individual users with the separate permissions, like co-owners, users who can edit and also share your app.