I am working on setting up OAuth on the Shopping API. So, for testing purposes I enabled OAuth on my sandbox keyset.
When I am trying to make calls to shopping API ( the sandbox one), the call is successful (200) but in the response body I get
<ShortMessage>Invalid item ID.</ShortMessage>
<LongMessage>Invalid or non-existent item ID.</LongMessage>
I even entered the correct ItemId inside request body. Despite that I am getting this error. Is there something I am doing wrong?