IIS Express Debug Mode Issue

Question

There is an issue when I debugging my backend net5.0 project. The issue is "Web server failed to listen on port 5001" then I changed port but the problem does not change.

Kitten

Port number could be blocked by a virus checker or another application is using the port. – Epaulet

Have you checked if the port is currently in use? Try a netstat -ab to check. – Aracelyaraceous

Might be a silly question and I don't know if your dev environment allows it, but have you set your DEV SSL port and HTTP port to the same port? i.e. 5001? – Aracelyaraceous

@Tomás I checked but it is not in use. – Kitten

{ "$schema": "http://json.schemastore.org/launchsettings.json", "profiles": { "Gateway.Command": { "commandName": "Project", "dotnetRunMessages": true, "launchBrowser": true, "launchUrl": "swagger", "applicationUrl": "https://localhost:5001;http://localhost:5000", "environmentVariables": { "ASPNETCORE_ENVIRONMENT": "Local" } } } } this is my launchSettings.json – Kitten

port can be used from antoher project when I debugged. – Kitten

when I changed my port also getting same error. waiting for the web server to listen on port 53855 and then same result web server failed to listen on port 53855 – Kitten

I think issue is changed. Actually not changed. we identified the problem that is wrong with net5.0. I can debug my project with net3.1 and net6.0 but net5.0 is not working. I installed .net5.0 sdk and I used to VS Community 2022 then I changed to VS Enterprise 2022 maybe issue caused by this. – Kitten

It's just waste of time to continue any investigation on .NET 5, as it reached end of life a while ago. VS2022 is known to stop supporting end-of-life technologies. – Paschal

Try opening VS as administrator, I believe internal communication between .net architecture and IIS. – Grosberg

Answer 1

I had the same issue after loading one of the existing project. I was able to resolve this by installing the .NET version project was targetting. (In my case, it was .NET 5).

Reason for the error: Since .NET's previous versions are out-of-support, Visual Studio won't install previous versions during installation.

Remedy: Intall SDK by yourself after installing Visual Studio

Belford

Since Visual Studio 2019 updating it has become a nightmare, updates have failed every single time and it gives cryptic error messages which are hard to understand and fix. I uninstalled Visual Studio 2019(which supports .NET 5) and installed Visual Studio 2022(which doesn't support .NET 5) and tried to run a .NET 5 project and got this error "Process with an id of ### is not running" and then "Web server failed to listen on port". Why could it not give a simple understandable error saying, "The project is targeting .NET 5 which is unsupported. Try upgrading to .NET 6."? This is beyond me. – Stylus

Answer 2

In my case that was

app.Run();

line deleted accidently from Program.cs

Killen

Answer 3

For me the issue was that i added some configuration to the appsettings.json file and i forgot to add a comma. fixing that and everything was back to work.

Darin

what is some configuration? – Via

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center. – Grearson

Goodness me, I wasted so much time on this. IntelliSense places a warning "Missing a comma after an object member" on the line in the appsettings.json file when you've got it open looking right at it but doesn't bother posting any warnings into the Error List tab where it would be easy to find. – Urquhart

Answer 4

If you are using application url with port and you are using different url port in the environment variables settings in some field like origin. Then this problem arises. You have to keep them same.

Awildaawkward

Actually I can debug another project. There is no problem. But this one does not work. It happens suddenly. – Kitten

Answer 5

I had a similar Issue after updating my packages, to fix it:

Make sure that the DotNet version in the csproj is the same as the version found in the following folders:

C:\Program Files\dotnet\shared\Microsoft.NETCore.App C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App

So my csproj was contained:

<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="7.0.4" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="7.0.4" PrivateAssets="all" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Authentication" Version="7.0.4" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="7.0.4" />
  </ItemGroup>

So I made sure that all the File locations specified above the csproj file had versions 7.0.4.

Fazeli

Answer 6

For me, this seemed to be caused by the random signing out of my Microsoft Account in Visual Studio 2022. As soon as I re-entered my creds, it went away.

Cobbie