Currently unable to edit microsoft word or excel, despite having annual Microsoft 365 subscription

Hi,

I currently have a microsoft 365 annual subscription (personal classic, renews Sep 26) and use Work and excel on my mac book (running MacOS Tahoe 26.6). When I open word I am unable to edit, only view), there are 2 banners at the top:

1. "check for updates" when i click on this it says: Excel 16.78, Powerpoint 16.78 and Word 16.78 - Upgrade required. However there is no way to click through to actually update them.
2. "Activate microsoft 365 to create and edit": when I click through on "already bought office? sign in?" and log in it says "Unknown error, code 0x0"

On researching microsoft 365 troubleshooting pages, there is a webpage giving instruction on this specific error message "code 0x0". It suggests updating the microsift apps via Microsoft AutoUpdate (MAU) from Finder > Applications > Microsoft AutoUpdate, however I do not have this option on my mac. It also suggests "If you don’t see MAU, check /Library/Application Support/Microsoft/MAU2.0/". Again I cannot find a way to update my microsoft apps via my mac.

Can anyone hep with this? I have raised a ticket with microsoft who say the engineers are working on it, but it seems to be taking a long time. Can anyone point me in the right direction please?

Thanks