Office key issue

Question

Microsoft Office key shows invalid, kindly check as the same has been obtained from system itself

Answer 1

If your Office licence was previously activated, when you activated Office that licence should have become associated to your Microsoft Account as a digital licence online and it is from there that you can re-install Office without the need for a product key:

https://account.microsoft.com/services/

Do you find your Office licence linked to your account on that link.

If not, where did you purchase your Office licence, was that from a 3rd party retailer or direct from Microsoft?