Can't connect to GitHub Package Registry from Visual Studio

In Visual Studio 2019, I'm trying to connect to our private GitHub Package Registry but keep getting unauhorized error.

Here's what I've done:

1. Created a Personal Access Token (PAT) on GitHub with Write access to packages.
2. I then created a nuget.config file with following code and placed it in c:\Users\My_User_Name\AppData\Roaming\NuGet\ folder.
3. I also tried placing this nuget.config file in the project root

I still get unauthorized error when I try to connect to our GitHub Package Registry. Any idea what the problem is?

Here's the nuget.config file contents:

<?xml version="1.0" encoding="utf-8"?><configuration><packageSources><clear /><add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" /><add key="Our Corporate GitHub Packages" value="https://nuget.pkg.github.com/OUR_CORPORATE_ACCOUNT_ON_GITHUB/index.json" /><add key="Microsoft Visual Studio Offline Packages" value="C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\" /></packageSources><packageSourceCredentials><github><add key="Username" value="MY_GITHUB_USERNAME" /><add key="ClearTextPassword" value="MY_GITHUB_PERSONAL_ACCESS_TOKEN" /></github></packageSourceCredentials></configuration>