Fix IIS localhost:2996 Error in ASP.NET MVC (.NET Framework 4.8)
If you encounter the below error while running an ASP.NET MVC application in Visual Studio:
The Web Application Project is configured to use IIS. The Web server 'http://localhost:2996/' could not be found.
This issue commonly occurs due to legacy IIS settings stored inside the .csproj file.
Environment
- Visual Studio 2022
- ASP.NET MVC
- .NET Framework 4.8
- IIS Express
Root Cause
Even though IIS Express is enabled, the project may still be forced to use Local IIS due to legacy configuration
stored inside <ProjectExtensions> in the .csproj file.
The following settings hard-lock the project to port 2996:
<UseIIS>True</UseIIS> <DevelopmentServerPort>2996</DevelopmentServerPort> <IISUrl>http://localhost:2996/</IISUrl> <IISAppRootUrl>https://localhost:2996/</IISAppRootUrl>
Step-by-Step Solution
Step 1: Change IIS Express SSL Port
<IISExpressSSLPort>44321</IISExpressSSLPort>
Step 2: Close Visual Studio
Completely close Visual Studio before proceeding.
Step 3: Delete Cached Folders
.vs bin obj
Step 4: Reset IIS Express Configuration
C:\Users\<username>\Documents\IISExpress\config\applicationhost.config
Step 5: Fix the .csproj (Critical Step)
Change:
<UseIIS>True</UseIIS>
To:
<UseIIS>False</UseIIS>
Delete the following entries completely:
<DevelopmentServerPort>2996</DevelopmentServerPort> <IISUrl>http://localhost:2996/</IISUrl> <IISAppRootUrl>https://localhost:2996/</IISAppRootUrl> <OverrideIISAppRootUrl>True</OverrideIISAppRootUrl>
Step 6: Delete User Override File
DPTextiles.csproj.user
Step 7: Reopen and Run
- Open the solution
- Set project as Startup Project
- Press F5
Expected Result
The application should now run successfully using IIS Express:
https://localhost:44321/
Key Learnings
- <UseIIS> has higher priority than <UseIISExpress>
- ProjectExtensions can silently override Web settings
- .csproj.user can break IIS configuration
Best Practices
- Use IIS Express for local development
- Avoid hard-coding Local IIS URLs
- Keep solution name and project name different
Author: Arulkumar Sivaraj
