Codes are typically tied to a single user account. If you bought a used physical copy, the previous owner may have already registered the key. Why You Should Avoid "Free" Online Keys
If your code is being rejected, check for these common mistakes: Codes are typically tied to a single user account
Look closely at characters like 0 (zero) vs O (letter), or 1 (one) vs I (capital i). Codes are typically tied to a single user account
Are you having trouble with a during the activation process? Codes are typically tied to a single user account
If bought through stores like Humble Bundle or GOG, the key is located in your account's digital library or order history. Troubleshooting Common Key Errors