Hi Ryan,
Thanks for your reply - please see my reply embedded below:
Krestrel is usually denoted by "commandName": "Project" in the launchSettings.json. These launch settings only apply to your local environment, there you need to change your application url setting back to "applicatinUrl": "http://localhost:5000".
So launchSettings.json is "only" used in my local environment - i.e. not used when I publish to Azure (I did not realise this was the case and hence my confusion). Thanks for the clarification.
So, you can get around CORS issue by using relative paths (.e.g ~/api/method) rather than a full URL. This will allow you to test your changes locally and push them to Azure without having things break.
I updated my React front-end to use relative paths and this also addressed the CORS issue (thanks).
Another option would be to use appsettings.json that configures sets ApiEndpoint which you can then add to your Azure App Service Application Settings.
I am not sure I understand what you mean by setting "ApiEndpoint" (perhaps you can provide a link explaining this configuration). I did however do some searching and I found a very useful YouTube video explaining how to configure appsettings.json for development/production - see: h9hlN0DOKRM
With regards to my appsettings.json my current setup does not have any configurations that set the port my WEB API is listening on. Am I correct in thinking that if no specific port configuration options reside within appsettings.json then by default the WEB API (for production) will be configured to listen on port 80/443?
Thanks again for your help.
Spencer