I have been moving round trying to use the manual method still do not work, what I did was to delete it to see if I could download it back (add) but it refuses. Seems there is no hope for that, I am only window store now downloading my firefox to see if I can use it on that browser.
Have you tried downloading it from here?
You can try re-downloading and installing this [
Extension] by enabling Developer Mode, and let me know the results.
Then drag&drop it (with developer mode enabled) in the extensions management page
chrome://extensions/