MicrosoftBrilliant! Ever since I started writing my first ASP.NET Core web app in .NET 8, then in .NET 9, I was always getting Error 503.0 The Server has shut down! I thought I better look deeper into the issue, so I found this post and it all made sense. I was calling WebApplication.CreateBuilder and even WebApplication.CreateSlimBuilder just to get to builder.Configuration.GetConnectionString(id) as I have multiple databases that I need to switch to. I was doing this in all Controllers! I was able to get around this by injecting IConfiguration into the Controller. Also for Static Classes I added public static IConfiguration Configuration; to a Static Class called AppExtensions and then added AppExtensions.Configuration = builder.Configuration; to my Program.cs code. Now I have the best of BOTH worlds without the error anymore.
