Help with SP-API getting InvalidInput

Hey everyone,

I’m trying to call the getOrderItems endpoint using Postman and I keep running into the following error:
{

"errors": [

{

"code": "InvalidInput",

"message": "The input you have submitted is not valid. Please check your input and try again.",

"details": ""

}

]

}

Here’s the documentation I’m following:

• https://developer-docs.amazon.com/sp-api/reference/getorderitems
• Endpoint: https://sellingpartnerapi-eu.amazon.com/orders/v0/orders/{orderNumber}/orderItems

{orderNumber} is in the standard Amazon 3-7-7 format (for example, 205-8070955-3272313).

I’ve already:

• Enabled all roles(you’ll just have to take my word for it since I can’t attach images here haha).
• Granted PII access.
• Confirmed that my access token is valid and included in the header.

Still getting the same “InvalidInput” response.

Also noticed Amazon updated their documentation today/within 18 hours, for example, this link that worked yesterday now gives a 404:
https://developer-docs.amazon.com/amazon-shipping/reference/label-purchase-via-purchase-shipment-api

Has anyone else run into this recently? Could Amazon have changed something in how order IDs or tokens are validated? Any help or insight would be appreciated!