If you’ve encountered HTTP Error 502.5 – ANCM Out-of-Process Startup Failure, you’re likely working on a .NET Core application that is facing difficulties during startup. This error is often linked to issues between your application and the ASP.NET Core Module (ANCM), which is responsible for managing how your .NET Core application runs on the server.
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What Causes HTTP Error 502.5 – ANCM Out-of-Process Startup Failure?
- Missing or Corrupted .NET Core Runtime
One of the most common causes of HTTP Error 502.5 – ANCM Out-of-Process Startup Failure is that the required .NET Core runtime version is missing or not properly installed. This is frequently seen in environments like Azure App Service or IIS. - Configuration Issues in IIS or Azure
A misconfigured web server such as IIS or Azure App Service can also trigger the HTTP Error 502.5 – ANCM Out-of-Process Startup Failure. If the process cannot start due to configuration settings, this error will be displayed. - Uncaught Exceptions in the Application
If your application has an uncaught exception during startup, the ANCM cannot initialize the application, resulting in a 502.5 error. This is particularly common in .NET Core 2.2 and .NET Core 6 applications. - Environment-Specific Issues
This error can also occur when moving applications between environments (e.g., from development in Visual Studio to production in Azure App Service), especially if configuration files are not updated accordingly.
Fixing HTTP Error 502.5 – ANCM Out-of-Process Startup Failure
1. Install the Correct .NET Core Runtime
Ensure that the right version of the .NET Core runtime is installed on your server. This is especially important if you are working with specific versions like .NET Core 2.2, .NET Core 6, or .NET Core 3.1.
You can verify the installed runtimes by running the following command:
dotnet --info2. Check IIS and Azure App Service Configuration
If you’re deploying to IIS or Azure App Service, ensure that the correct configuration is in place. The HTTP Error 502.5 – ANCM Out-of-Process Startup Failure IIS issue can often be resolved by making sure the web.config file is properly set up.
3. Debugging in Visual Studio
If you’re developing your application in Visual Studio and encounter the HTTP Error 502.5 – ANCM Out-of-Process Startup Failure Visual Studio, check the output window for detailed logs. Enable detailed error logging to catch issues during startup.
4. Review Application Logs
In cases where uncaught exceptions cause the error, reviewing the application logs can help identify the root cause. Add logging capabilities to capture detailed error messages during the startup process.
5. Update .NET Core Framework
Older versions of .NET Core, such as .NET Core 2.2 or .NET Core 3.1, may have bugs or incompatibility issues that lead to startup failures. Upgrading your application to a stable release such as .NET Core 6 or .NET 8 can help resolve the error.
Special Cases: HTTP Error 502.5 in Different Environments
HTTP Error 502.5 – ANCM Out-of-Process Startup Failure Azure App Service
When deploying your application to Azure App Service, you may face this error if the server lacks the required runtime or if the configuration file is incorrect. Make sure the app settings in Azure match the runtime version and check the deployment logs for errors.
HTTP Error 502.5 – ANCM Out-of-Process Startup Failure Swagger
The Swagger API documentation tool may also trigger the HTTP Error 502.5 if the application startup fails before Swagger initializes. Ensure the middleware for Swagger is correctly configured in your Startup.cs file.
IIS HTTP Error 502.5 – ANCM Out-of-Process Startup Failure
To solve this issue in IIS, ensure that your Application Pool is configured to use the correct No Managed Code setting, and that your IIS server has the required .NET Core Hosting Bundle installed.
Related Questions and Answers
Conclusion
The HTTP Error 502.5 – ANCM Out-of-Process Startup Failure can occur for several reasons, including missing runtimes, application configuration issues, or uncaught exceptions during startup. By checking your .NET Core runtime versions, reviewing logs, and ensuring your server is properly configured, you can resolve this error and successfully launch your application. Whether you’re working with IIS, Azure App Service, or Visual Studio, following these troubleshooting steps will guide you through fixing this common error.
