404 Not Found error for nuget feed

I’m using Visual Studio 2019 and am trying to add the nuget feed to install the SDK

However, I’m getting the error
[TestProject] The V2 feed at ‘https://www.nuget.org/packages/TestProject.OpenSDK/Search()?$filter=IsLatestVersion&searchTerm=’’&targetFramework=‘net45%7Cnet452’&includePrerelease=false&$skip=0&$top=26&semVerLevel=2.0.0’ returned an unexpected status code ‘404 Not Found’.

in the Package Manager console
Any ideas what’s going on?

OK, answering my own question here. So it seems that the documentation in TestProject needs to be updated for Visual Studio 2019 (maybe earlier). The nuget feed should be

https://api.nuget.org/v3/index.json

in order to search for the TestProject Open SDK It throws the above error if you use the nuget.org link.