• GitHub Extension for Visual Studio version: 2.3.4.40
• Visual Studio version: 2017

What happened (with steps, logs and screenshots, if possible)

1. Clone new repository.
   git clone https://github.com/bitcoin/bitcoin.git
2. Launch Visual Studio 2017 and File > Open > Folder... and select the bitcoin folder.
3. Open GitHub pane (via Team Explorer > Pull Requests).
4. Select a PR. If that works, try the next one...

Check the logs at: C:\Users\<user>\AppData\Local\GìtHūbVisualStudio\extension.log.

LibGit2Sharp.LibGit2SharpException: Failed to receive response: The server returned an invalid or unrecognized response
   at LibGit2Sharp.Core.Ensure.HandleError(Int32 result)
   at LibGit2Sharp.Core.Proxy.git_remote_fetch(RemoteHandle remote, IEnumerable`1 refSpecs, GitFetchOptions fetchOptions, String logMessage)
   at LibGit2Sharp.Commands.Fetch(Repository repository, String remote, IEnumerable`1 refspecs, FetchOptions options, String logMessage)
   at LibGit2Sharp.Network.Fetch(Remote remote, FetchOptions options)
   at GitHub.Services.GitClient.<>c__DisplayClass8_0.<Fetch>b__0() in C:\source\github.com\github\VisualStudio\src\GitHub.App\Services\GitClient.cs:line 78
   at LibGit2Sharp.Core.Ensure.HandleError(Int32 result)
   at LibGit2Sharp.Core.Proxy.git_remote_fetch(RemoteHandle remote, IEnumerable`1 refSpecs, GitFetchOptions fetchOptions, String logMessage)
   at LibGit2Sharp.Commands.Fetch(Repository repository, String remote, IEnumerable`1 refspecs, FetchOptions options, String logMessage)
   at LibGit2Sharp.Network.Fetch(Remote remote, FetchOptions options)

System.NullReferenceException: Object reference not set to an instance of an object.
   at LibGit2Sharp.Network.Fetch(Remote remote, IEnumerable`1 refspecs, FetchOptions options)
   at GitHub.Services.GitClient.<>c__DisplayClass9_0.<Fetch>b__0() in C:\source\github.com\github\VisualStudio\src\GitHub.App\Services\GitClient.cs:line 106
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
   at GitHub.Services.GitClient.<GetPullRequestMergeBase>d__24.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.App\Services\GitClient.cs:line 396
<GetPullRequestMergeBase>d__17.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSessionService.cs:line 256
   at GitHub.InlineReviews.Services.PullRequestSession.<GetMergeBase>d__11.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 97
   at GitHub.InlineReviews.Services.PullRequestSession.<UpdateFile>d__17.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 170
   at GitHub.InlineReviews.Services.PullRequestSession.<GetFile>d__10.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 80
   at GitHub.ViewModels.PullRequestDetailViewModel.<CreateChangedFilesTree>d__104.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.App\ViewModels\PullRequestDetailViewModel.cs:line 523
   at GitHub.Services.GitClient.<GetPullRequestMergeBase>d__24.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.App\Services\GitClient.cs:line 396
   at GitHub.InlineReviews.Services.PullRequestSessionService.<GetPullRequestMergeBase>d__17.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSessionService.cs:line 256
   at GitHub.InlineReviews.Services.PullRequestSession.<GetMergeBase>d__11.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 97
   at GitHub.InlineReviews.Services.PullRequestSession.<UpdateFile>d__17.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 170
   at GitHub.InlineReviews.Services.PullRequestSession.<GetFile>d__10.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.InlineReviews\Services\PullRequestSession.cs:line 80
   at GitHub.ViewModels.PullRequestDetailViewModel.<CreateChangedFilesTree>d__104.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.App\ViewModels\PullRequestDetailViewModel.cs:line 523
   at GitHub.ViewModels.PullRequestDetailViewModel.<Load>d__100.MoveNext() in C:\source\github.com\github\VisualStudio\src\GitHub.App\ViewModels\PullRequestDetailViewModel.cs:line 389