It might be a different error, then. The specific message I'm getting in my browser (on Automata Empire, which I picked at random):
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<Error>
<Code>SignatureDoesNotMatch</Code>
<Message>
The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.
</Message>
<StringToSign>GET 1505441309 /itchio/upload2/game/59781/288466</StringToSign>
</Error>