Perpetual Office Home & Business 2019 for Mac license

Hello, I need help restoring activation of a perpetual Office Home & Business 2019 for Mac license that I purchased in January 2024.

The license is still clearly shown under Products you've purchased in my Microsoft account as “Office Home & Business 2019 for Mac.”

Recently, Word stopped allowing me to work and began asking me to purchase a Microsoft 365 subscription. I have never needed Microsoft 365 because I purchased a perpetual Office license.

I have already tried the following:

• Completely uninstalled Office.
• Reinstalled Office from my Microsoft account, but Microsoft automatically installs the current version (16.106), which does not activate with my Office 2019 license.
• Manually downloaded and installed Office/Word version 16.78, which is supposed to support Office 2019.
• Attempted to sign in and activate using the Microsoft account that owns the license.

I now receive “Unknown Error — An unknown error has occurred. Error code: 0x0” when attempting to activate.

I am not asking for technical support for an unsupported product. I am asking Microsoft to restore my ability to activate and use a perpetual license that I purchased, that remains associated with my Microsoft account, and that Microsoft recognizes as owned by me.

Please help me activate my Office Home & Business 2019 license. I do not want to purchase a Microsoft 365 subscription or another Office license to regain access to software for which I already purchased a perpetual license.

Thank you.