It seems they have changed their website URL from enjoygineering.com to mounty.app.
Unfortunately, they forgot to replace the server certificate. So now it's not possible to access the website, as the cert and the URL doesn't match.
I meticulously followed mounting and un-mounting procedure and it still corrupted my drive's directory. The Mounty website's recommended solution is to use Tuxera to fix it. Software that costs US$31. Seems like Mounty is really designed to sell Tuxera products.
Works perfectly and without any fuss. First time I launched it it let me know that it detected a mounted Bootcamp volume and asked me if I wanted to make it writeable. Perfect.
Just one complaint: the menu icon of a blue mountain is WAY too wide and takes up too much precious real estate. Shrink that and I'll change my review to 5 stars!