Update Install Failed

## Environment data
`dotnet --info` output: .
NET Core SDK (reflecting any global.json):
Version: 3.1.402
Commit: 9b5de826fd

Runtime Environment:
OS Name: Windows
OS Version: 10.0.18363
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\3.1.402\

Host (useful for support):
Version: 3.1.8
Commit: 9c1330dedd

.NET Core SDKs installed:
2.1.104 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.403 [C:\Program Files\dotnet\sdk]
2.1.500 [C:\Program Files\dotnet\sdk]
2.1.511 [C:\Program Files\dotnet\sdk]
3.1.402 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download

VS Code version:
Version: 1.50.1 (system setup)
Commit: d2e414d9e4239a252d1ab117bd7067f125afd80a
Date: 2020-10-13T15:06:15.712Z
Electron: 9.2.1
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Windows_NT x64 10.0.18363
C# Extension version:

## OmniSharp log
[could not find]

## Steps to reproduce
Open Visual Studio Code
Navigate to Extensions via the icon on left
Under "RECOMMENDED" click on C# 1.23.4 C# for Visual Studio Code ...
In the main window, click on the green *Install* button.
Observe the message toast "Failed to install 'ms-dotnettools.csharp'. - followed by button "Download Manually"
Click on "Download Manually" button, new browser window (tab) opens at: https://marketplace.visualstudio.com/_apis/public/gallery/publishers/ms-dotnettools/vsextensions/csharp/1.23.4/vspackage
HTML Returned:

{"$id":"1","innerException":null,"message":"Request was blocked due to exceeding usage of resource 'Count' in namespace 'AnonymousId'. For more information on why your request was blocked, see the topic \"Rate limits\" on the Microsoft Web site (https://go.microsoft.com/fwlink/?LinkId=823950).","typeName":"Microsoft.TeamFoundation.Framework.Server.RequestBlockedException, Microsoft.TeamFoundation.Framework.Server","typeKey":"RequestBlockedException","errorCode":0,"eventId":3000}

## Expected behavior
At first, tried to update the extension: expected it to install.
Removed and tried to install again: expected extension to install.

## Actual behavior
Upon update: error message: failed to install - download manually button appears.
Upon install: error message: failed to install - download manually button appears.