worked, thanks suport for helping me.

100 % Work and much easier to follow now!

1. Install the MS Office 2021 from ISO file
2. Open any Office app like Word
3. Enter Product Key (given by the seller) when asked
4. You will get a popup that has Installation ID (IID) ie 9 groups of 7 digits (don't close the popup till end).
5. Go to https://visualsupport.microsoft.com (https://aka.ms/aoh)
6. Click on "Lets Get Started"
7. Login to your own Microsoft account
8. Enter Installation ID (IID)
9. Copy Confirmation code
10. Enter Confirmation code in the Popup of your Microsft office App
11. You have now succesfully completed your Activation and product is now linked directly to your Microsoft account.

Works 100000000000000000000000000000000000000000000%

The old school activation process via phone (and robot voice) wasn't working for me anymore. I had to go to aka.ms/aoh to activate, but that wasn't working with my installation id. Thanks to support, I did receive a key that (in combination with installation id and the new ms activation page) worked like a charm. Thank you, and keep up!