Call of Duty: Warzone is a complex game, and it occasionally experiences bugs. One of these is Activision account registration error 0. This error says there was a problem with your Activision Account, and asks you to try logging in again. Here’s what this means and what you can do to fix Activision account registration error 0.
How to fix Activision account registration error 0
Account registration error 0 appears when there’s a problem with your Activision email address. Specifically, it appears when you try to register an Activision account with an email address already used for another Call of Duty account.
To fix the problem, you should first think about why it appeared to begin with. If you’ve logged in before without encountering this problem, do as the message says: Close the game and try logging in again. With any luck, it will go through on the next try. Of course, there’s always a chance that this error may appear when the game servers are experiencing problems. In fact, that’s the cause of many random Call of Duty errors.
On the other hand, if this is your first time registering for Warzone, you’ll need to use a different email. Registration error 0 only appears when there’s a conflict with a given email address. Each Activision or Call of Duty account can only be tied to one address; one email, one user. It’s not possible to register multiple accounts using the same email address, though one user can register with multiple addresses.
As to why your first email address was refused, only you can say. Perhaps you signed up and forgot your login details? If so, contact Activision Support. They should be able to help you un-link any past accounts if needed. Assuming that’s not the case, simply try using a different email address. It might be a pain, but it will get you into the game without any more registration problems.