Can you show the full screen of the Speedgrader page? The screenshot you have does not show the download link in either the upper left corner or below the "Submitted files" area.
Is the .docx file able to be downloaded from the Speedgrader page? It looks like the download link in the upper left corner is missing, and the one in the right side is greyed out...
Are you able to actually give a grade for the assignment? As far as I know (as A Canvas admin), the ability to annotate with DocViewer is tied to the "Grades - Edit" permission. Knowing whether or not you can put a grade in and save it might help troubleshoot this issue.