So, i made a custom widget and added it into Portal as a Web App Builder Extension by using the manifest.json URL. It seems to be a successful deploy, as it even shows up in my Web App Builder, in the custom widget tab, but upon clicking "OK" after selecting my custom widget, nothing happens. Nothing. I can add normal pre-built widgets just fine, it's just my widget that won't work.
We are getting the same issue when trying to use a custom widget deployed in a web server (on a different machine). When you say you only needed to add the web.config file at root level you are talking about the 'parent folder' in which you have all the custom widgets? Could you indicate the CORS settings in that file?
