In-App Purchase failure in the apple's review, but works in the Testflight

My game already contains various IAP Products and passed an Apple's Review a few days ago.

However, I submitted a new version today that includes a new IAP product, but Apple rejected my submission due to the failure of purchase.

In the Testflight with Sandbox account, there was no issue with the purchase. The only they gave to me is just the screenshot of when the purchase failed.

Here's what they told me:

We found that your in-app purchase products exhibited one or more bugs when reviewed on iPad running iOS 14.3 on Wi-Fi.

Specifically, the app displayed an error message after completing the payment.

After some research, I found that some people having a similar issue got a response from Apple that there is a problem with App Review Test Network.

Even there was the same man who just resubmitted rejected app without changed anything, but it was approved.

The IAP works in the Testflight with Sandbox environment without any problem. Is there anything that I missed?

the Same issue as well. how to fix , please help me

In-App Purchase failure in the apple's review, but works in the Testflight
 
 
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