Application's URL http or https

[Shopisight]

This is to seek clarification regarding the URL of our application when launched/opened in Shopify development store.

There is a mismatch between the actual URL of the application and the one that Shopify is launching. In the application's app set up page we have given the URL with http but when Shopify is launching it is taking URL with https and saying "{app-URL} took too long to respond".

Could you please confirm if https is mandatory for an application that is deployed in Shopify.