We have just installed a new XenApp 7.15 environment and once we configured and tried to access the store address on the Storefront server we received the following error:
Cannot complete your request.
Upon a short investigation, we have discovered that you have to change the Loopback communication setting on the Storefront server.
Connect to the Storefront server | Select Store
In the right pane select Manage Receiver for Web Sites
Click Configure | Advanced Settings
From the Enable loopback communication drop-down list choose OnUsingHttp
You should be able to navigate your store now.