QUESTION: How can I use the sandbox Account to test subscription with the Watch?

We want to test auto renewable subscription in the sandbox.

On my personal iPhone is my personal production account. On my personal iPhone is a sandbox account.

But: When I want to buy subscription in the sandbox on the watch, then the watch shows the error: "Buying the app is not possible. Login with your iPhone with the Apple Watch App with your Apple-ID."

When I take a look in the watchApp --> General --> AppleId then I see my production account.

QUESTION: How can I use the sandbox Account to test subscription?

QUESTION: How can I use the sandbox Account to test subscription with the Watch?
 
 
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