I'm encountering an "InvalidInput" error when trying to retrieve a single order from the SP-API sandbox environment. The API returns "Could not match input arguments" despite using what appears to be the correct endpoint structure.

API Call Details

Endpoint:

GET https://sandbox.sellingpartnerapi-na.amazon.com/orders/v0/orders/902-1845936-5435065

Request-Headers:

x-amz-access-token: [valid token]

Content-Type: application/json

Response:

json{

"errors": [

{

"code": "InvalidInput",

"message": "Could not match input arguments",

"details": ""

}

]

}

What I've Tried

Verified the order ID format is in the required 3-7-7 format

Removed quotation marks around the order ID

Used a fresh access token with appropriate permissions

Double-checked that the endpoint structure matches the documentation

Questions :

Are there any additional required parameters for the /orders/v0/orders/{orderId} endpoint in the sandbox environment?

Is the marketplaceIds parameter required for this specific endpoint? Documentation isn't clear on this point.

Are there specific test order IDs that must be used in the sandbox environment?

Are there any known differences between how the production endpoint and sandbox endpoint handle the getOrder operation?

Any guidance would be greatly appreciated as I'm trying to complete my SP-API integration testing.

Thanks in advance!