A few weeks back I was investigating an issue with a SharePoint Add-in. I had created a second App file to point to the new App location on Azure. The Client ID remained the same within the web app (as its contained within web.config) and the app file upon publish. That’s when I received:
“The endpoint address ‘https://myapp-QA.azurewebsites.net/Services/AppEventReceiver.svc’ does not match the app’s endpoint ‘myapp-DEV.azurewebsites.net’.”
I had gone through all the project property files, extracted the contents from the .app file and even did a full text search on the entire directory for my old ‘myapp-DEV’ and had not found any clue as to where this was coming from. But then I remembered…
The App Registration (AppRegNew.aspx) is where this value was coming from. Your App file as well as your projects may have the correct address, but the domain MUST match the value provided in App Registration on SharePoint. Unfortunately there is no way to update this value once created without having to change out your client ID — So be very cautious when creating an app registration.