• Download & Install:
  • .NET Core Hosting Bundle
  • Microsoft URL Rewrite
• Restart the IIS service.
• Setup new IIS Website:
  • Open IIS on the server.
  • Right click the Sites folder and select "Add website"
  • enter site name
  • set the physical path to the Vue.js app directory
  • leave the host name empty → click "OK".
• Right click the new site and select "Add Application"
  • enter the alias "api" (without quotes)
  • set the physical path to the ASP.NET Core api directory
  • click "OK".
• In Application Pools
  • right click the app pool for the new site → "Basic Settings"
  • change the .NET CLR version to 'No Managed Code'.
  • right click the app pool for the new site → "Advanced Settings"
  • set ‘Identity’: LocalSystem
  • Make sure "web.config" is as given in the article below! Vue.js + ASP.NET
    & inside the Vue.js front-end folder

additional resources:

• Vue.js + ASP.NET Core on Azure with SQL Server - How to Deploy a Full Stack App to Microsoft Azure
• IIS URL Rewrite – Hosting multiple domains under one site
• Host ASP.NET Core on Windows with IIS
• Hosting Vue JS SPA build on Microsoft IIS