"Get it now" for Claude for Microsoft 365 add-in (WA200010725) redirects to a 404 page - installation impossible

I'm trying to install the "Claude for Microsoft 365" add-in from Marketplace/AppSource on a Microsoft 365 Personal account (Excel desktop). The add-in previously worked correctly, then it broke with an authorization error, and I had to remove it. Now, when I try to reinstall it, it no longer appears in Excel's built-in Add-ins Store / "My Add-ins" list at all.

I then tried the direct Marketplace listing: https://marketplace.microsoft.com/en-us/product/office/WA200010725

Clicking "Get it now" and completing the "Confirm your details" form redirects to:

https://pages.store.office.com/addininstaller.aspx?assetid=WA200010725&...

which returns an HTTP 404 "Page not found" error. This happens consistently, in multiple fresh/independent browser sessions and even after signing out and back in. Checking my Microsoft account order history (account.microsoft.com/billing/orders), no order/acquisition for this add-in is ever created - confirming the failure happens server-side during the acquisition flow, not just as a broken confirmation page.

I already have a paid Claude Pro subscription, so the separate Claude plan requirement (confirmed with Microsoft support) is met on my side.

I already contacted Microsoft support via live chat (case number 7108960503) and was advised to also post here so the engineering team is aware.

Has anyone else run into this same 404 error when trying to acquire this add-in from AppSource/Marketplace? Any updates on a fix would be appreciated.