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The Alliance strongly recommends that you generate bypass codes as a backup for when your registered devices are not available. You will also need a bypass code to access your account if you lose all of your second factors. To do that you just have to go onto their web page above: Multifactor Authentication Management
 and click in the button "Generate 10 codes, each valid for one use" resp. "Générer 10 codes, chacun valide pour une seule utilisation" (on the bottom left of the page).

Connecting with multifactor authentication

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