Your Office key does not work — the real reasons

You enter the 25-character code and Office answers with an error. Before you decide the key is faulty, it is worth going through the list below — in most cases the problem lies elsewhere and can be solved without a replacement.

1. The edition does not match

The most common cause. A key for Professional Plus will not activate an installed Home and Business, and a key for 2021 will not activate an installed 2019.

How to check: open Word → File → Account. It shows the exact edition and year. Compare it with the one the key is for. If they do not match, uninstall and install the correct version — the key is fine.

2. There are remnants of an old Office on the computer

The second most common. A previous installation or a Microsoft 365 trial version is left half-removed and blocks the new activation.

Solution: Settings → Apps → Installed apps, remove everything with Microsoft Office and Microsoft 365 in the name, restart, then install again. If uninstalling fails, Microsoft has an official tool for complete removal (Office Uninstall Support Tool).

3. A mistake while typing

It sounds trivial, but it happens constantly. The key contains only capital Latin letters and digits. Watch out for 0 and O, 1 and I, 5 and S, 8 and B.

Solution: copy the code straight from the email instead of typing it, and take care not to pick up a space at the start or the end.

4. The key has already been activated elsewhere

One licence is for one device. If the code has been used on another computer, it will be refused here.

5. There is no internet, or a firewall is blocking it

Activation goes through Microsoft's servers. A workplace network, a VPN or an overly strict antivirus can cut the connection.

Solution: try from another network, for example mobile internet, or temporarily switch off the VPN.

6. The wrong Microsoft account

If Word is signed in with one account while the licence is recorded in another, Office cannot see the entitlement. Check the top right to see which email you are signed in with.

7. The date and time on the computer are wrong

Rare, but real. The activation servers reject requests with a mismatched date.

Solution: Settings → Time & language → turn on setting the time automatically.

If online activation is refused despite everything

Telephone activation remains:

1. In the activation window choose "I want to activate the software by telephone".
2. You will see an Installation ID — a long number in groups.
3. Take a screenshot and send it to us at info@litsenzi.bg with your order number.
4. We send back the confirmation code, which you enter in fields A to H.

When the key really is the problem

If you have been through everything above and Office still refuses, send us your order number and a picture of the error message. We check it and replace the key free of charge; if the replacement does not help either, we refund the amount. The statutory guarantee of conformity is 2 years.

This is also the difference from a key bought from a questionable source: there, nobody can check it and nobody can replace it. How to recognise such a seller — in this article.

Do not have a key, or need a different edition? See the Office licences.