Associated Domain not working to Open App

Hello Having trouble getting associated domain to work in our project. It was working when we used Branch, but our company wants to host the domain ourselves.

This is a multi-scheme project, using .xcconfig files to define the correct entitlement per Build. The relevant entitlement file has: <key>com.apple.developer.associated-domains</key> <string>applinks:bm.ddcas.ai</string> in the ....{other irrelevant test associated domains....}

The project Team and App ID are taken from the Identifiers screen where the Identifier capabilities has 'associated domains' ticked on. I've also checked elsewhere on AppleDeveloper/Connect to be sure.

When we used Branch with domain key app links: bmstores.app.link this worked fine.

With https://bm.ddcas.ai (our own host) which is publicly available and has an aasa file in both the main directory and /.well-known, typing this in safari or anything just doesn't attempt to link to the App.

The iPhone is in developer mode, and using the developer menu associated domains diagnostic tool, typing https://bm.ddcas.ai results in the diagnostic saying 'The url is a Universal Link for the app with identifier **********.***etc (the app is installed on real iPhone 12, iOS 18.6.2 and my Xcode is 16.4)

However, it just doesn't work if we type in https://bm.ddcas.ai and results in a Safari message of '400 not found' and the 'nginx' shows.

We have read innumerable Apple Dev posts and StackOverflow posts, as well as several step by step 'how to's' online but this just isn't working.

The aasa file is at https://bm.ddcas.ai/apple-app-site-association and is setup as follows: { "applinks": { "apps": [], "details": [ { "appID": "{my Team ID}.{my App ID}", "paths": [ "*" ], "components": [ { "/": "/verification", "?": { "verification_code": "[A-Za-z0-9]{6}" }, "comment": "Matches verification code path" } ] } ] } }

Our Server guys say the website (bm.ddcas.ai) is public and hosted, it just doesn't have a /verification path as they say it should redirect before reaching that. Also, our Android redirect works using this site, so this appears to be something specific Apple code is looking for.

What, please, are we likely to be missing as it does not seem obvious from the Apple documentation or any of the resources I have checked online. Normally we can figure anything out, but getting nowhere here so the help is appreciated.

Associated Domain not working to Open App
 
 
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