Troubleshoot document access denial

I am getting this message when I open my document URL. Help! Cannot figure out what I have done wrong - it worked prior to this.

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>Access Denied</Message> <RequestId>VFN87XHBQMBPTT0M</RequestId> <HostId>ZwsItvtUmYrz+zoSQD+4NNKULFqPAafW56yvumX9piRjV22hpyieax5gXGpo18ai/zBxk9yF8Ik=</HostId> </Error>