We got following feedback from the approval team when we ask for the Shopify URL (Shop name) and perform Oauth request as described in Shopify authentication procedure:
When encouraging a merchant to install additional apps or connect the app to another store, apps must use the standard install process initiated from the app listing.
You can't request a merchant's .myshopify.com URL.
I am trying to approve unlisted App, so how merchants (my web application users) should connect their shop?
Even if it is an unlisted app that no store will ever install through the Shopify app store, to get approved they say you must still make it install successfully as if someone clicks 'Add App.' The way you test this in development is create multiple development stores and then in your partner dashboard go to More options > test on my development store > install and confirm that it installs / uninstalls correctly on your different development stores using that link.
I already support the flow you described, if someone click 'Add App' at Shopify shop he will successfully install and connect to my web application.
Because the app is unlisted, as far as I understand this is a flow that is only relevant at the testing stage...
So I need to remove the part we ask for the Shopify URL on my web application?
if so, my question remained: how merchants (my web application users) should connect their shop?
I don't ask it after installation, my work flow is starting in my web application, the users enter their shop and perform Oauth request (I do not understand what other possibility there is).
Anyway I will do what you suggested and after my app will approved I will ask for the shop...
Thank you very much.