WebView2 fails to initialize on Outlook with Exception (0x8007139F)

Description
We have a working VSTO Add-in that uses WebView2 and for a specific user, WebView2 fails to initialize every time. I also tried with a minimal add-in with just a WebView2 window on a task pane and I get the same result.
The exception, taken from the InitializationException property on the event InitializationCompleted, is as follow:

System.Runtime.InteropServices.COMException (0x8007139F): The group or resource is not in the correct state to perform the requested operation. (Exception from HRESULT: 0x8007139F)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode)
   at Microsoft.Web.WebView2.Core.CoreWebView2Environment.<CreateCoreWebView2ControllerAsync>d__37.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Web.WebView2.WinForms.WebView2.<InitCoreWebView2Async>d__13.MoveNext()

How can I get to the root cause of the error? The same add-in on other Office applications work fine for the same user.

Version
SDK: 1.0.864.35
Runtime: Runtime 91.0.864.59
Framework: WinForms
OS: Win10 21H1, Outlook 16.0.14131.20116 64-bit.

Repro Steps

1. Open a task pane with a WebView2 in Outlook.
2. Check event InitializationCompleted

Expected: Initialization is Successful
Actual: Initialization fails with provided exception

We specify a UserData folder, but it is not shared by applications other than Outlook.
No special properties are set in the initialization.

AB#34287773

Start with the minimal WinForms Outlook add-in and the InitializationCompleted event, using the provided CoreWebView2Environment.CreateCoreWebView2ControllerAsync stack trace and version details. Reproduce the failure with the specified UserData folder and determine the root cause of the Outlook-only initialization error; done means the cause and a confirmed resolution are documented.