Cannot activate my purchased Office Home and Student 2021(Chi)(Full AMCS79GOFFHS21C

Hi, I am looking for technical support. I have a Mac running macOS 17, and I purchased a lifetime Office Home & Student 2021 perpetual license back in 2023. This license is successfully bound to my Microsoft account: ******@gmail.com.

However, over the last two days, I suddeny cannot type anything in Word or Excel. A bar at the top or bottom of the screen says 'Activate Microsoft 365 to Create and Edit.' When I click 'Activate' and sign in with my correct email address and password, it repeatedly fails with an error saying 'No License Found,' and forces me to purchase or subscribe to Microsoft 365.

I have already tried the following troubleshooting steps over the past two days, but the issue persists:

1. I logged into microsoft.com and confirmed that my 2023 purchase record for 'Office Home & Student 2021' is active and listed under my products.
2. I downloaded and re-installed the correct installer from that section, but the applications remain locked after installation.
3. I ran the official Microsoft Office License Removal Tool (Microsoft_Office_License_Removal_2.7.pkg) to wipe out old cached data. It gave me a successful green checkmark, but upon reopening Word and signing in again, it still falls back to the same 'No License Found' and Microsoft 365 prompt.

Since I have already gone through all the standard troubleshooting steps to no avail, could an engineer please assist me ? I need help to completely purge the stuck Microsoft 365 subscription cache on my MacBook and reactivate my legitimate Office 2021 license. Thank you!"