[.net] Nuget connection attempt failed "Unable to load the service index for source"

While trying to connect to Nuget, I'm getting the error below, and then I am unable to connect:

[nuget.org] Unable to load the service index for source https://api.nuget.org/v3/index.json. An error occurred while sending the request. Unable to connect to the remote server A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

I am able to access https://api.nuget.org/v3/index.json on my browser.

This question is not a duplicate. The other answers don't solve my problem.

This question is related to .net visual-studio nuget

The answer is

I was getting the same error while trying to browse the NuGet Package, to resolve the same followed below step

1- go to %appdata%\NuGet\NuGet.config

2- Verify the urls mentioned in that config

3- Remove the url which is not required

4- Restart visual studio and check

In my case i had had Fiddler running which had changed my proxy settings

I encountered this error when trying to set up NuGet packages inside locally hosted Gitlab instance. The error indicated 401 Unauthorized code. The solution was removing offending source with:

nuget source Remove -Name SOURCE_NAME

And then adding the same source, but this time specifying the username and password in the command:


Go to

Settings ( Global Settings of your PC ) > Network and Internet > Proxy > Automatic Proxy Setup > and set Automatically detect settings to off.

in my case i had to add the sources in the Visual studio Options->NugetPAckageManager->sources and then restart the visual studio command prompt

I have resolved this issue using below steps

  1. Click on run search this %APPDATA%\NuGet\NuGet.config.

  2. Open the setting and add this http_proxy keyin NuGet.config.

  3. Then you will able install the BouncyCastle.Crypto.dll in your application.

Thank you! Responses are welcome if you help this answer.

Something may have change your proxy setting, like Fiddler. Close Fiddler, then close Visual Studio and open it again.

The error can be caused by just temporary network issue, and disappear, if try again.

In support of the answer provided by @Eddie Chen (here) I had to add http_proxy setting to following file as well:


<add key="http_proxy" value="http://your_proxy_url:8080" />

  1. go to %appdata%\NuGet\NuGet.config

  2. Modify this line:

        <add key="Microsoft Visual Studio Offline Packages" value="C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\" />
        <add key="Package source" value="https://api.nuget.org/v3/index.json" />

In my case, the problem was that I was building on a, older virtual machine which was based on Win7.

I found this fix from https://github.com/NuGet/NuGetGallery/issues/8176#issuecomment-683923724 :

nuget.org started enforcing the use of TLS 1.2 (and dropped support for TLS 1.1 and 1.0) earlier this year. Windows 7 has TLS 1.2 disabled by default (check the DisabledByDefault value under HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client in your registry). To enable the support, please make sure you have an update (*) installed and switch the support on:

reg add HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client" /v DisabledByDefault /t REG_DWORD /d 0 /f /reg:32
reg add "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client" /v DisabledByDefault /t REG_DWORD /d 0 /f /reg:64
reg add "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client" /v Enabled /t REG_DWORD /d 1 /f /reg:32
reg add "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client" /v Enabled /t REG_DWORD /d 1 /f /reg:64

The (*) update referred to was Microsoft kb3140245: Update for Windows 7 (KB3140245)

I installed the update, rebooted (as requested by the update), added those registry keys, and then Nuget worked fine.

I'm using VSO/Azure DevOps.

You can also visit the feed url directly in your browser. You may end up with a response that contains a message like this, which may make your diagnosis a lot quicker:

The user does not have a license for the extension ms.feed.

It seems Nuget still uses the proxy script address (for our VPN) even though the proxy settings are disabled. I removed the script address and it works.

enter image description here

If you are getting this error, but you don't have a proxy server, you can go to


And comment this lines:

     <!-- Proxy settings -->
     <add key="http_proxy" value="host" />
     <add key="http_proxy.user" value="username" />
     <add key="http_proxy.password" value="encrypted_password" />

It worked for me because I was getting that error, but I don't have a proxy server.

I had this error and then I realized I was logged in with my personal Microsoft account instead of my work account.

Hope this helps.

If using Visual Studio 2019, just delete the "defaultproxy" section if you are not using any default proxies in devenv.exe.config. in VS 2017 this section was not present


<defaultProxy enabled="true" useDefaultCredentials="true">
    <proxy bypassonlocal="True" proxyaddress="http://<yourproxy:port#>"/>


<!--<defaultProxy enabled="true" useDefaultCredentials="true">
    <proxy bypassonlocal="True" proxyaddress="http://<yourproxy:port#>"/>

Else provide the appropriate proxy username and password.

Maybe this helps

For me removing the .nuget folder located in C:\Users\YourNameHere fixed the problem.

Some development environment may not be using neither a browser nor a proxy.

One solution would downloading the package from nugget such as the https://dotnet.myget.org/F/dotnet-core/api/v3/index.json to a shared directory then execute the following:

dotnet add package Microsoft.AspNetCore.StaticFiles -s "shared drive:\index.json"

I hope that works for you.  

It is worth noting that there was a bug with .net core SSL authentication that could cause this. Disabling their latest networking stack implementation, solved this issue for me.

You can set this permanently or just launch your app using:


I had the same error message while scaffolding Identity to my ASP.NET Core MVC project. Since my connection was not behind a proxy, removing/editing proxy configurations didn't make sense. And I didn't want to delete a file or uninstall PMC either. While looking around I realized a "Clear All Nuget Cache(s)" button on Tools --> Options --> NuGet Package Manager --> General. After pressing the button I had to wait for some time for the operation to complete. After that I tried to scaffold the Identity again but it didn't work. Then I decided to restart VS and voila :)

enter image description here

Go to -> Tools -> Extensions and Updates and uninstall NuGet package manager.. restart visual studio and reinstall it.... every thing will set to normal

Deleting the %AppData%\NuGet\NuGet.Config and restarting VS2019 worked for me.

Similar to https://github.com/NuGet/Home/issues/3281

In my case it is happened because I don’t have internet connection and it is trying to scaffolding

I had a similar issue trying to connect to my private TFS server instead of the public NuGet API server. For some reason I had an issue between the AD server and the TFS server so that it would always return a 401. The NuGet config article shows that you can add your AD username and password to the config file like so:

          <add key="Username" value="[email protected]" />
          <add key="Password" value="this is an encrypted password" >
          <!-- add key="ClearTextPassword" value="not recommended password" -->

This is not quite an ideal solution, more of a temporary one until I can figure out what the problem is with the AD server, but this should do it.

In my case, I just restarted the docker and just worked.

I couldn't resolve the problem itself, but found a way to install packages.

Just specify nuget.org as a source directly in Package Manager Console.

Update-Package -reinstall -Source nuget.org

I had a similar problem while trying to execute Install-Package Modernizr on Visual Studio 2015. I fixed my problem by following the below steps:

  1. Download the package from its online source.
  2. Go to Tools/NuGet Package Manager/Package Manager Settings.
  3. Select Package Sources from the window.
  4. Add a new package source by clicking on the + sign. Enter a name and source location by clicking on ... (triple dot) sign.
  5. Make sure that only the package source that you've just added is checked. Uncheck all the other package sources.
  6. Go to Package Manager Console and type Install-Package Modernizr.
  7. Visual Studio 2015 installs the package automatically and creates Scripts and packages folders in your root folder.

I hope the same solution works while installing other packages, too.

Setting of your PC -> Network And Internet Proxy -> Automatic Proxy Setup then set Automatically detect settings to off and clear the Script Address

If you see error as follow, you may need to set up your Azure Artifacts Credential, see this Github link, you could either install the credential provider by running a powershell script or manually.

error :   Response status code does not indicate success: 401 (Unauthorized).

If you are behind a company proxy and on Mac, just make sure your http/https checkboxes are checked and applied.

Open Registry Editor by pressing Win + R and type regedit Enter

Navigate to:

\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.3\Client

Change the value of DisabledByDefault key 0 to 1

Then restart the Visual Studio.

Read more about TLS
Read more about this issue w.r.t. NuGet

nuget restore 


msbuild /t:restore

both didn't work for me with same error. But

dotnet restore 

worked perfect. Try that

I was trying to add an Azure Artifacts NuGet source.

I followed Microsoft's instructions here, with one critical oversight.

I forgot to replace /v3/index.json with /v2.

enter image description here

I was using an older version of Nuget on VS2010, where it defaults to TLS 1.0 here it can be fixed by changing the default TLS version used by .Net framework which is configured in Registry keys

reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SystemDefaultTlsVersions /t REG_DWORD /d 1 /f /reg:64

reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SystemDefaultTlsVersions /t REG_DWORD /d 1 /f /reg:32


NuGet.org will permanently remove support for TLS 1.0 and 1.1 on June 15th. Please ensure that your systems use TLS 1.2.

You can refer to this link for info on TLS 1.2 support

Make sure docker is running in your local machine. build command will work but its required running docker to get network data.

I think it will help.

I was getting this same error while running RUN dotnet restore in my Dockerfile using docker-compose up command in Windows 10.

enter image description here

I have tried all the possible solution provided on the internet and was also keep an eye on this open issue. Finally, after spending more than 8 hours, by following the preceding steps, I was able to fix my issue.

  1. Uninstall Docker from your system
  2. Restart your system
  3. Install Docker from this link. Below is the version of my Docker

    enter image description here

  4. Restart your system

  5. Start Docker for Windows, search Docker in the search bar in Windows. Make sure it is running.

  6. You should also go to Services.msc and make sure the services Docker Engine and Docker for Windows Service are running.

    enter image description here

  7. At last, you must check your Nuget.config file from C:\Users\{Username}\AppData\Roaming\NuGet. For me, the content of that file was as below.

    <?xml version="1.0" encoding="utf-8"?> <configuration> <packageSources> <add key="nuget.org" value="https://api.nuget.org/v3/index.json" /> </packageSources> <packageRestore> <add key="enabled" value="True" /> <add key="automatic" value="True" /> </packageRestore> <bindingRedirects> <add key="skip" value="False" /> </bindingRedirects> <packageManagement> <add key="format" value="0" /> <add key="disabled" value="False" /> </packageManagement> </configuration>

    Hope this helps.

I have stumbled across this issue when trying to run nuget.exe via Jenkins (configured as a service, by default using Local System account). I have edited C:\Windows\System32\config\systemprofile\AppData\Roaming\NuGet\NuGet.Config file which looks like the following:

<?xml version="1.0" encoding="utf-8"?>
        <add key="http_proxy" value="http://proxy_hostname_or_ip:3128" />
        <add key="https_proxy" value="http://proxy_hostname_or_ip:3128" />

    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />


In order to test command prompt can be started via PSTools:

psexec -i -s CMD

and actual test run in the newly created cmd windows (runs as Local System):

path_to_nuget\nuget.exe restore "path_to_solution\theSolution.sln"

Installing fiddler was causing me similar problem. Uninstalling fiddler and removing the fiddler proxy from the machine.config (from both Framework and Framework64) solved the problem.

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