[iOS] Adding Books to Hyphen reader

I need some help please, I just started using Hyphen on my iPad Pro. When I tried to add books by clicking on Add Books>More>Calibre Companion; the error message comes up ""Failed to launch Calibre Companion" The document picker "Calibre Companion" failed to launch (4099)". This is also happening on my iPhone 6S Plus.

I am posting this in both Calibre Companion and Apple Devices for Hyphen.