Error installing or upgrading docfx from command line

[lawsonmcw]

I just attempted to update docfx from the command line and got the error below. On a different machine I uninstalled docfx and then attempted a clean install and got the same NullReferenceException. It looks like perhaps an issue with Nuget? Any ideas on how can I get this installed from the command line to be globally accessible as before? Thank you.
Regards,
Lawson

C:\Windows\system32>dotnet tool update docfx --global
Unhandled exception: System.NullReferenceException: Object reference not set to an instance of an object.
at NuGet.Protocol.PackageMetadataResourceV3.ProcessRegistrationPage(RegistrationPage registrationPage, List1 results, VersionRange range, Boolean includePrerelease, Boolean includeUnlisted, MetadataReferenceCache metadataCache) at NuGet.Protocol.PackageMetadataResourceV3.GetMetadataAsync(String packageId, Boolean includePrerelease, Boolean includeUnlisted, VersionRange range, SourceCacheContext sourceCacheContext, ILogger log, CancellationToken token) at NuGet.Protocol.PackageMetadataResourceV3.GetMetadataAsync(String packageId, Boolean includePrerelease, Boolean includeUnlisted, SourceCacheContext sourceCacheContext, ILogger log, CancellationToken token) at Microsoft.DotNet.Cli.NuGetPackageDownloader.NuGetPackageDownloader.GetPackageMetadataAsync(PackageSource source, String packageIdentifier, Boolean includePrerelease, Boolean includeUnlisted, CancellationToken cancellationToken) at Microsoft.DotNet.Cli.NuGetPackageDownloader.NuGetPackageDownloader.GetMatchingVersionInternalAsync(String packageIdentifier, IEnumerable1 packageSources, VersionRange versionRange, CancellationToken cancellationToken)
at Microsoft.DotNet.Cli.NuGetPackageDownloader.NuGetPackageDownloader.GetBestPackageVersionAsync(PackageId packageId, VersionRange versionRange, PackageSourceLocation packageSourceLocation)
at Microsoft.DotNet.Cli.ToolPackage.ToolPackageDownloader.GetNuGetVersion(PackageLocation packageLocation, PackageId packageId, VerbosityOptions verbosity, VersionRange versionRange, Boolean isGlobalTool)
at Microsoft.DotNet.Tools.Tool.Install.ToolInstallGlobalOrToolPathCommand.GetBestMatchNugetVersion(PackageId packageId, VersionRange versionRange, IToolPackageDownloader toolPackageDownloader)
at Microsoft.DotNet.Tools.Tool.Install.ToolInstallGlobalOrToolPathCommand.ExecuteInstallCommand(PackageId packageId)
at Microsoft.DotNet.Tools.Tool.Install.ToolInstallGlobalOrToolPathCommand.Execute()
at Microsoft.DotNet.Tools.Tool.Update.ToolUpdateGlobalOrToolPathCommand.Execute()
at System.CommandLine.Invocation.InvocationPipeline.Invoke(ParseResult parseResult)
at System.CommandLine.ParseResult.Invoke()
at Microsoft.DotNet.Cli.Program.ProcessArgs(String[] args, TimeSpan startupTime, ITelemetry telemetryClient)

[lawsonmcw]

I was able to reinstall docfx by specifying the source like so: dotnet tool install docfx -g --source "https://api.nuget.org/v3/index.json". Previously I'd been experimenting with nuget and custom package sources and it's possible something got misconfigured there along the way which caused this error. Hopefully this helps someone that runs into similar error messages.