I don’t know how this could happen, but the string for the access group is wrong in your entitlements.
It should be
$(AppIdentifierPrefix)com.wishlists-app.group instead of
Your extension must have the same app group and keychain group activated. I can’t see anything of your app extension. Then you must also call
useUserAccessGroup("SN26HDFT24.com.wishlists-app.group") in your extension.
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