Troubleshooting: HTTP Error 500.30 ASP.NET Core app failed to start

This error occurs when the ASP.NET Core Module attempts to start the .NET Core CLR in-process, but does not succeed, preventing the application from starting. The cause can usually be determined by checking the Application Event Log and the ASP.NET Core Module stdout log.

This screenshot displays the startup error page, along with common solutions and troubleshooting steps

How to identify the exception

1. Open the Windows Event Viewer or the Azure Event Log for Azure App Service.

2. Look for an event containing Level `Error` and Source `.Net Runtime`. This is followed by two other events containing Source `IIS AspNetCore Module V2`.