We implemented digital signatures on our app quite some time ago, as we are using the order-level issue_refund endpoint on the fulflilmnt API:
https://developer.ebay.com/api-docs/sell/fulfillment/resources/order/methods/issueRefund
We were able to successfully implement this and it is still working to date. However we now have need to utilise some of the Post Order API endpoints that also require a signature, specifically Approve Cancel Request, Issue Return Refund and Process Return Request. For these endpoints we are consistently getting the error "Signature validation failed to fulfil the request" - despite the fact that we are using the same code util to create the signature headers.
Has anyone else experienced this?
