I am developing an app using Web AppBuilder within ArcGIS Online. The data are hosted in in-house SQL Server, not in ArcGIS Online. I have tested deploying in IIS, it works well, no issues. While accessing the app externally through ArcGIS Online, the app does open, but the operational layers does not appear as these are hosted in SQL Server internally. I need to deploy this app in a live environment so that the authorised groups can get access externally. I reckon this has to be done through a web server, but can anyone please tell me the necessary steps to follow? My worry and I am bit concerned about whether hosting data internally in SQL server would be an issue, or will this work?? Appreciated for your advise and suggestions. Thanks very much in advance!