You'll have to add the method again, following the steps in the Set up text messages section of this article. Important: If you delete text messaging by mistake, there's no way to undo it. If you no longer want to use text messages as a security info method, you can remove it from the Security info page. Delete text messaging from your security info methods If you want to make text messaging your default method, see the Change your default security info method section of this article. Your security info is updated and you can use text messaging to verify your identity when using two-step verification or password reset. Type the code sent to you through text message to your mobile device, and then select Next. On the Phone page, type the phone number for your mobile device, choose Text me a code, and then select Next. On the Add a method page, select Phone from the list, and then select Add. Select Security info from the left navigation pane or from the link in the Security info block, and then select Add method from the Security info page. Sign in to your work or school account and then go to your My Account page.

Note: If you want to receive a phone call instead of a text message, follow the steps in the Set up security info to use phone calls article.

Microsoft mfa setup