This is usually solved by clearing Internet Explorers cache (as the launcher is actually piggybacking off IE).

So if you load up Internet Explorer (not Edge, and yes even if you normally browse using something else) and then go into the options and you can delete the browsing history, specifically "Temporary Internet files and website files". On that same page make sure that "Preserve Favourites website data" is NOT ticked.

Then after deleting that, the launcher will likely work again as expected.