Using a protocol as a CMS link

Hey there,

I am trying to add a protocol instead of a Http link in a cms link box but i keep getting an error “Should be a valid url like “”.”

I have tried to add a backtick (`) at the front of the link, but it also gives me an error.

Example of one of my protocols: ms-windows-store://pdp/?productid=9PB1C8S0922M

Many thanks.