'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 68.232.34.200:443

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.

Solution 1:^[1]

You need to add proxy settings into Nuget.Config file. Refer to this link for details: Nuget Config Section & Nuget Proxy Settings.

Solution 2:^[2]

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

Solution 3:^[3]

A developer of the nuget-package manager suggested in 2019 to disable tls 1.3 as a workaround (see issue 7705).

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.

3rd party edit

Be aware that this disables tls 1.3 for the os not just for nuget or dotnet.
Windows 10 version 1909 did contain an experimental implementation of TLS 1.3 but later versions should be fine. Based on one answer from Unable to browse nuget packages you can test if tls is the problem via a console programm

static async Task Main(string[] args)
{
    var client = new HttpClient();
    string uri = "https://apiint.nugettest.org/v3-index/index.json";
    var response = await client.GetAsync(uri);
    string msg = "If you see this, your machine has no TLS/SSL issues with nuget.org";
    Console.WriteLine(msg);

}

Solution 4:^[4]

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

Solution 5:^[5]

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"?>
<configuration>
    <config>
        <add key="http_proxy" value="http://proxy_hostname_or_ip:3128" />
        <add key="https_proxy" value="http://proxy_hostname_or_ip:3128" />
    </config>

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

</configuration>

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"

Solution 6:^[6]

Go to

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

Solution 7:^[7]

Simple :

Close VS2019
Go to C:\Users\you\AppData\Roaming\NuGet
Delete the file NuGet.Config
Relaunch VS2019

You're good to go !

Solution 8:^[8]

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).

Solution 9:^[9]

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:

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

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.

Solution 10:^[10]

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

%userprofile%\AppData\Roaming\NuGet\NuGet.Config

And comment this lines:

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

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

Solution 11:^[11]

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:

DOTNET_SYSTEM_NET_HTTP_USESOCKETSHTTPHANDLER=0 dotnet ...

Solution 12:^[12]

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

Solution 13:^[13]

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

Solution 14:^[14]

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

Solution 15:^[15]

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

FYI

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

Solution 16:^[16]

One of your nuget sources may be unreachable.

At the moment of writing, AspNetCore (https://dotnet.myget.org/F/aspnetcore-dev/api/v3/index.json) seems to have an expired certificate or have been removed entirely.

Simply removing the nuget source from your settings should solve this issue

Solution 17:^[17]

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 :)

Solution 18:^[18]

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

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.

Solution 19:^[19]

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.

Solution 20:^[20]

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

Solution 21:^[21]

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.

Solution 22:^[22]

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

Solution 23:^[23]

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

change

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

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

Else provide the appropriate proxy username and password.

Solution 24:^[24]

nuget restore

and

msbuild /t:restore

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

dotnet restore

worked perfect. Try that

Solution 25:^[25]

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:

Download the package from its online source.
Go to Tools/NuGet Package Manager/Package Manager Settings.
Select Package Sources from the window.
Add a new package source by clicking on the + sign. Enter a name and source location by clicking on ... (triple dot) sign.
Make sure that only the package source that you've just added is checked. Uncheck all the other package sources.
Go to Package Manager Console and type Install-Package Modernizr.
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.

Solution 26:^[26]

Tested on Windows 7

Step1 : Open Command window (run cmd) Step 2: Run the following commands to enable TLS 1.2 support if it is disabled (adding REGISTRY Entries):

"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

Solution 27:^[27]

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

C:\Windows\system32\config\systemprofile\AppData\Roaming\NuGet\NuGet.Config

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

Solution 28:^[28]

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

Solution 29:^[29]

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

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.

Uninstall Docker from your system
Restart your system
Install Docker from this link. Below is the version of my Docker
Restart your system
Start Docker for Windows, search Docker in the search bar in Windows. Make sure it is running.
You should also go to Services.msc and make sure the services Docker Engine and Docker for Windows Service are running.
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.

Solution 30:^[30]

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

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Eddie Chen - MSFT
Solution 2	janonimus
Solution 3	surfmuggle
Solution 4	iliketocode
Solution 5
Solution 6	VISHAL TANK
Solution 7	Hashka
Solution 8	Jonathan Chow
Solution 9	Hydromast
Solution 10	RJFalconer
Solution 11	firetiger77
Solution 12	hosam hemaily
Solution 13	Michael Freidgeim
Solution 14	Sylvain Rodrigue
Solution 15	Sahil Guleria
Solution 16	Prince Owen
Solution 17	heuristican
Solution 18
Solution 19	Phani Kumar M
Solution 20	Dooie
Solution 21	ps2goat
Solution 22	Shwe
Solution 23	Aditya Mishra
Solution 24	Vladimir Zotov
Solution 25	Ramil Aliyev
Solution 26	user2274515
Solution 27	jitin14
Solution 28	Kadeer Mughal
Solution 29	Community
Solution 30	lemon

'Nuget connection attempt failed "Unable to load the service index for source"

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