how to get wow on iphone

How do I use a WoW Authenticator?

my account was hacked recently and i got it again and I have a real in my iPhone, I want to know is is there a unique code to enter or I can just use one of the codes that appear every 30 seconds. please explain i no nothing about these authenticators.

With either system, which you have to use the new code is given. With, say, an hour ago, will not work (I've tried).

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