No packages will install

[Sampleeeee]

Details about Problem

NuGet product used (NuGet.exe | VS UI | Package Manager Console | dotnet.exe):
Jetbrains Rider UI

NuGet version: 5.5.0

dotnet.exe --version: 2.1.512

VS version: Community 2019

OS version: Version 1909 (OS Build 18363.720)

Detailed repro steps so we can see the same problem

1. Right click on project

2. Manage NuGet Packages

3. Choose any package, so far I have tested Newtonsoft.Json, CitizenFX.Core.Client, and CitizenFX.Core.Server

4. Install the package

5. Get error:

Severity	Code	Description	Project	File	Line	Suppression State
Error		Exception 'System.AggregateException' thrown when trying to add source 'http://packagesource'. Please verify all your online package sources are available.
One or more errors occurred.
Unable to load the service index for source http://packagesource.
An error occurred while sending the request.
The remote name could not be resolved: 'packagesource'				

Other suggested things

Verbose Logs

Unsure of how to do this on Visual Studio 2019, if someone can tell me how, I'd happily do it.

Sample Project

I'll just zip the project I'm currently using
MarvosaCADServer.zip

[donnie-msft]

Please review the Package Source documentation. It looks like you have an improperly configured source pointing to http://packagesource.

[nkolev92]

Closing this per the above answer.

#8420 is tracking an improvement on config discovery and #7973 is tracking config management.