Error reading package

System.AggregateException: One or more errors occurred. (An error occurred while sending the request.) (The given header was not found.)
 ---> System.Net.Http.HttpRequestException: An error occurred while sending the request.
 ---> System.Net.Http.HttpIOException: The response ended prematurely. (ResponseEnded)
   at System.Net.Http.HttpConnection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpConnection.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.DecompressionHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.<SendCoreAsync>g__Core|4_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.<SendCoreAsync>g__Core|4_0(HttpRequestMessage request, Boolean useAsync, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
   at Relativity.APIReference.Entry.OpenAsync() in C:\Dev\relativity.apireference\Data\PackageData.cs:line 46
   at Relativity.APIReference.Entry.Open() in C:\Dev\relativity.apireference\Data\PackageData.cs:line 33
   at Relativity.APIReference.PackageData.ReadNuspec(Entry entry) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 372
   at Relativity.APIReference.PackageData.ReadAsync(HttpClient httpClient, String packageUri) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 365
   at Relativity.APIReference.PackageData.PackageDataCache.ReadPackageFromUrl(PackageData package, HttpClient httpClient, CancellationToken token) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 598
   at Relativity.APIReference.PackageData.PackageDataCache.GetValueAsync(String arg0, PackageVersion arg1, HttpClient httpClient, CancellationToken token) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 578
   --- End of inner exception stack trace ---
 ---> (Inner Exception #1) System.InvalidOperationException: The given header was not found.
   at System.Net.Http.Headers.HttpHeaders.GetValues(HeaderDescriptor descriptor)
   at Relativity.APIReference.PackageData.ReadEntriesAsync(HttpClient client, String file) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 224
   at Relativity.APIReference.PackageData.ReadAsync(HttpClient httpClient, String packageUri) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 303
   at Relativity.APIReference.PackageData.PackageDataCache.ReadPackageFromUrl(PackageData package, HttpClient httpClient, CancellationToken token) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 598
   at Relativity.APIReference.PackageData.PackageDataCache.GetValueAsync(String arg0, PackageVersion arg1, HttpClient httpClient, CancellationToken token) in C:\Dev\relativity.apireference\Data\PackageData.cs:line 578<---