If you have your email host in GoDaddy you still can add the Coro add-in to the user's outlook.
Please follow the instructions:
Log in to your GoDaddy account -> Email & Office -> Admin -> Advanced -> Exchange -> sign In (must be admin account) -> Organization -> Add-Ins -> click on "+" -> add from URL -> insert the Coro Add-Inn URL -> Install -> after install double click on the Coro Add-Inn -> choose the option that fit your organization.