When you are setting up Microsoft Office Premium, you receive an error that prevents you from completing Office setup. This error only occurs in the Office setup that is associated with the following versions:
Office Personal Premium with Office 365 Services
Office Home and Business Premium with Office 365 Services
Office Professional with Office 365 Services
This error tells you that you have already redeemed the Office offer by using another Microsoft account from the one that you entered.
In most cases, you will perform the complete setup of Office from entering the product key, signing in with your Microsoft account, and installing the Office suite on your computer. In other cases, you cannot complete the setup and must restart the setup. If you successfully redeemed the Office product key the first time by using an associated Microsoft account, you receive this error if you try to redeem the offer again by using a different Microsoft account ID. However, if you enter the same Microsoft account ID the second time, you can successfully complete the installation.
The easiest way to resolve this issue is to restart the setup process and enter the same Microsoft account ID that you used the first time that you ran the setup. Remember which Microsoft account you used to redeem your Office offer. This is because you will have to sign in by using that account when you go to your Office My Account page to provision some additional services and to access links to reinstall Office if there is a Windows reset on your device.
You can also go to the Office My Account page and install Office from there.