apple-app-site-association correct configuration

Question

I am trying to implement an associated domain for an app I'm working on. So far, I have:

• Enabled the Associated Domains capability of the app
• Added all required domains with applinks:www.domain.com
• added an apple-app-site-association file to the root of my server, and when that didn't work also to the .wellknown on my server

This didn't work. When I go to the page that is supposed to open a view controller in my app, it doesn't redirect but only show the banner instead. When I tap the 'Open' button on the banner, however, the right view controller in my app is shown.

Then:

• I tried changing the mime type of the file, from application/json to application/pkcs7-mime.
• I verified there is no .json extension
• I verified that my server returns a valid response code (200), doesn't redirect, provides the file over https (I havent encrypted it).
• I verified the file has valid JSON.
• I even checked in my browser whether it finds the file and it does.
• Finally, I have copy-pasted the URL in notepad on the iPhone, long-pressed it and the option 'Open in App' appeared.

Nothing appears to be wrong, yet iOS doesn't link to the app in any circumstances, it only shows the Banner.

What am I missing here? How can I get safari to open my app instead of just showing the banner?

P.S. please note: The website of this project is an asp .net application