If you want to play the game securely, it is best to use official channels: Online Gaming Risks & Game Security - Kaspersky
There are several types of serial numbers associated with Anno 2070: Anno 2070 Serial Number List
Anno 2070 uses a strict activation limit system. Unlike modern "always online" checks, this older DRM ties a serial number to specific hardware IDs. If a key has been used by someone else—or if the list has been circulating for years—that key is permanently burned. Inputting a "found" key usually results in a generic error message or an instant flag on your Uplay account. The game essentially becomes unplayable because the servers recognize the key as stolen or over-used. If you want to play the game securely,
Q: Where can I find my Anno 2070 serial number? A: You can find your Anno 2070 serial number on the game's packaging, receipt, email confirmation, or Ubisoft account. Inputting a "found" key usually results in a
: If you bought a used physical copy, the key is likely already tied to the previous owner's account. Ubisoft does not allow the transfer of keys between accounts.
: If you buy a used physical disc, ensure the previous owner has transferred the account or that the key hasn't been activated, though this is rare for modern digital-rights-managed games. How to Activate Your Key Open the Ubisoft Connect desktop application. Click the Menu icon in the top-left corner. Select Activate a key .