Cannot add or update NuGet packages, receiving NuGet V2 feed error

I have recently moved to VS 2019 and now I can not install or update packages through NuGet. I receive the following error -

An error occurred while retrieving package metadata for 'jQuery.3.4.1' from source 'NuGet.org'.
Failed to fetch results from V2 feed at 'https://www.nuget.org/FindPackagesById()?id='jQuery'&semVerLevel=2.0.0' with following message : Response status code does not indicate success: 404 (Not Found).
Response status code does not indicate success: 404 (Not Found).

I have NuGet Package source pointing to --- https://api.nuget.org/v3/index.json

Is there another package source I should be using?