I’m developing a private application using the sp-api from Amazon.
And I want to create a Listing service to sell my used book so I’m using the Feeds API.

I always use the x-amz-token for the moment. I fetch it in my middleware and send in it to amazon in the request header and it always worked.

Even for createFeedDocument: without it, it doesn’t work. With it everything is good.

But once i do the uploadFeed request i keep getting an error :

<?xml version="1.0" encoding="UTF-8"?>
<Error>
<Code>AccessDenied</Code>
<Message>There were headers present in the request which were not signed</Message>                         <HeadersNotSigned>x-amz-access-token</HeadersNotSigned>
<RequestId></RequestId>
<HostId></HostId>
</Error>

And when I check on the documentation for uploadFeed or in the useCase for Feed (v2021) I dont find anything about it.

I watch this video from Amazon Seller University too and in the doc they talk about selfAuthorized in the developer panel. Is it what I need to do here ? Or do I need more something else to fix the error ?