Troubleshooting .NET 8 Application Errors Print

Overview

This guide covers common errors when running .NET 8 applications on Plesk Windows hosting and their solutions.

Enabling Detailed Errors

First, enable stdout logging to see detailed errors:

1. Edit web.config in your httpdocs folder
2. Set stdoutLogEnabled="true"
3. Ensure the logs folder exists

<aspNetCore processPath="dotnet" arguments=".MyApp.dll" 
            stdoutLogEnabled="true" 
            stdoutLogFile=".logsstdout" />

Common Errors and Solutions

HTTP Error 500.30 - ASP.NET Core app failed to start

Causes:

• Missing dependencies
• Incorrect .NET version selected
• Application startup exception

Solutions:

• Verify .NET 8 runtime is selected in Hosting Settings
• Check stdout logs for specific exception
• Ensure all NuGet packages are included in publish

HTTP Error 502.5 - Process Failure

Causes:

• Application crashes on startup
• Missing .NET runtime

Solutions:

• Republish as self-contained if runtime issues persist
• Check Event Viewer logs (contact support for access)

HTTP Error 500.35 - ANCM Multiple In-Process Applications

Cause: Multiple apps trying to run in same application pool

Solution: Ensure each .NET Core app has its own application pool or use out-of-process hosting

HTTP Error 404 - Page Not Found

Causes:

• Application not running
• Routing misconfiguration

Solutions:

• Verify Application Startup File is correct in Hosting Settings
• Check that Program.cs configures routing correctly
• Restart the application pool

Connection String Errors

For SQL Server connection issues, add TrustServerCertificate=True to your connection string:

Server=localhost;Database=mydb;User Id=user;Password=pass;TrustServerCertificate=True;

Checking Logs

1. Go to Files in Plesk
2. Navigate to logs folder in httpdocs
3. Open the latest stdout log file

Still Having Issues?

Contact support with:

• The exact error message
• Contents of stdout log
• Your .NET 8 project type (Web App, API, Blazor)