I can highlight the domain and open fine in Firefox on android. It doesn't render as the unicode glyph in the address bar after resolution though
Also resolves in Firefox on macOS
Resolves and loads fine on Firefox and Chrome on Windows 10
This is a cool looking website, but I don't think I'd ever use their service without knowing the people behind it or even where their office is located. Also I believe without an imprint this site is not GDPR compliant.
The domain resolved for me in Chrome on macOS though!