Unable to download course files

I apologize if someone has already made this comment - I just now tried to download the course documents.

Below is the error message I get when trying to download the course documents. Have tried on 2 browsers.

This XML file does not appear to have any style information associated with it. The document tree is shown below.

<Error>

<Code>AccessDenied</Code>

<Message>Request has expired</Message>

<X-Amz-Expires>900</X-Amz-Expires>

<Expires>2018-08-22T21:19:32Z</Expires>

<ServerTime>2018-08-23T12:41:10Z</ServerTime>

<RequestId>E0A0658D9459369C</RequestId>

<HostId>

8xS61fKVEIPpOxFomNMREbtigDCbwJzokzZQGsifJl6wsoTYtCB1pjraidtxRpixGDOVeTT/ymU=

</HostId>

</Error>

Thanks for your guidance with all these courses!! I've been having a really fun time following along. Excited to see what I can create as we continue on.