Any website promising a "free fixed activation code" is likely either:

Alternatively, if you need free access to Kaspersky, note that they offer a free version (Kaspersky Free) that requires no license key—only an activation within the app. Would you like a legitimate guide on that instead?

If you actually paid for a code but are seeing an error message saying it is invalid or "fixed" (perhaps you are seeing an error about the key being for a different region), here is the solution:

, you can "fix" this by recovering the code through official channels: My Kaspersky Portal : Log in to My Kaspersky and check the Subscriptions