@leokhoa I managed to fix this as follows:
In Chrome, open the Inspector > Network then make sure it's recording and go to the page you are trying to view (it will then fail with a DNS error). Then there is a clear browser cache link in the right window, click that and voila! So... don't ask me why clearing browsing history and flushing the cache the regular way did not work, but anywhooo... I can now work!