Cancellation Documents for InventoryGenExits and InventoryGenEntries

Hi, I am wondering if via anyone used cancellation documents feature via Service Layer?

I am following example provided and getting an error message attached. ID definietely exists and it always gives following error message.

POST https://localhost:50000/b1s/v1/InventoryGenEntries(123)/CreateCancellationDocument

Any advice would be helpful. Thanks

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