I have a sales channel that is framed within Shopify admin interface and I have set the security restriction on it iframe according to Shopify recommendation here: Setting up Iframe protection (shopify.dev)
The app is working fine now. However, when the user is selecting the subscription plan and get directed to Shopify to approve the charges he gets “redirected too many times error” and the only way to approve charges is to open the page on a new tab out of the frame.
The redirect url for Shopify subscription looks like the following: