Unable to enable Apple Pay for App Clip – “relationship 'undefined'” error when adding capability

Hey everyone, hoping someone here has run into this before.

I have a fully functional App Clip (com.didyoucatchit.app.Clip) linked to my main app (com.didyoucatchit.app). The Clip builds and runs perfectly, but I’m seeing issues trying to enable Apple Pay for it.

When I try to link my Merchant ID under the “On Demand Install Capable” capability in the Apple Developer portal, I get this error:

A relationship in the provided entity is not allowed for this request. The relationship 'undefined' can not be included in a 'bundleIdCapabilities' request.

Here’s what I have already configured and confirmed:

  1. App Clip capabilities in Xcode include:
  • Apple Pay Payment Processing
  • Associated Domains (appclips:app.didyoucatchit.com)
  1. Provisioning profile includes:
  • Apple Pay Payment Processing
  • Associated Domains
  • In-App Purchase
  • On-Demand Install Capable
  1. Entitlements file for the Clip:
<key>com.apple.developer.associated-domains</key>
<array>
  <string>appclips:app.didyoucatchit.com</string>
</array>
<key>com.apple.developer.in-app-payments</key>
<array>
  <string>merchant.com.didyoucatchit.app</string>
</array>
<key>com.apple.developer.parent-application-identifiers</key>
<array>
  <string>$(AppIdentifierPrefix)com.didyoucatchit.app</string>
</array>
  1. Merchant ID (merchant.com.didyoucatchit.app) is active and connected to Stripe

  2. Stripe Apple Pay configuration matches the same merchant ID and certificate

  3. Both provisioning profiles have been refreshed and downloaded

However:

The portal still throws the “relationship 'undefined'” error anytime I try to modify the Clip’s capabilities

In testing, Apple Pay doesn’t show up as a payment option in the Clip (using Stripe’s Payment Element integration)

Questions:

  1. Is this a known issue with the Developer portal when linking App Clips to merchant IDs?
  2. Is there a specific way to re-establish the parent–child relationship between the main app and the App Clip so the bundleIdCapabilities request includes the proper relationship JSON?
  3. Are there any additional configuration steps required when using Stripe for Apple Pay inside an App Clip?

System Setup:

  • Xcode: 16.2 (build 16C5032a)
  • macOS: Sequoia 15.3.1
  • iOS: 18.5 (testing on physical device)
  • Merchant ID: merchant.com.didyoucatchit.app
  • Main App ID: com.didyoucatchit.app
  • App Clip ID: com.didyoucatchit.app.Clip

Any help or insight would be hugely appreciated

Thanks in advance!

Unable to enable Apple Pay for App Clip – “relationship 'undefined'” error when adding capability
 
 
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