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Novaz AuthenticatorGET

Telekom Login (T-Online) 2FA: how to set up an authenticator app

By the Novaz team · Updated October 29, 2026
Novaz steps checked against version 1.0.5

On this page
  1. Turn on 2FA with an authenticator app
  2. Choose when Telekom asks for a code
  3. Trusted devices
  4. Mail apps use a separate password
  5. No backup codes
  6. If Telekom rejects your code
  7. Changing phones
  8. If you lose your authenticator
  9. Official Telekom help

If you have an @t-online.de email address, the account behind it is your Telekom Login. The same user name and password open the E-Mail Center, the Telekom Mail app, the Kundencenter, the MeinMagenta app, MagentaCLOUD and MagentaTV (Telekom). Even the E-MAIL LOGIN button on t-online.de uses it (Telekom).

Telekom calls two-factor authentication Mehr-Faktor-Authentifizierung (multi-factor authentication). It's optional and free, with codes by text message or from an authenticator app. Telekom rates the app as safer because it doesn't depend on the mobile network (Telekom). Turning it on doesn't automatically mean a code at every sign-in, though: you choose that separately. This guide uses Authenticator App - Novaz on iPhone, but any authenticator app works the same way.

How we checked this guide: the Telekom Login steps come from Deutsche Telekom's own help pages on telekom.de, linked below, which we read on October 20, 2026. We haven't tested them on a Telekom account, so a label may differ slightly. The pages are in German, so we give the German labels with a translation. The Novaz steps are checked against the app, version 1.0.5.

Turn on 2FA with an authenticator app

Telekom's step-by-step page describes this flow (Telekom):

  1. Sign in to your Login-Einstellungen (login settings) with your Telekom Login.
  2. Click Mehr-Faktor-Authentifizierung einrichten (set up multi-factor authentication).
  3. Choose Bestätigungscode per App (verification code by app). Telekom shows a QR code.
  4. In Novaz, tap +, then Scan QR code. If the QR code is on your iPhone's own screen, take a screenshot and use Choose a photo. See scanning a QR code on the same iPhone.
  5. Type the 6-digit code from Novaz into the field in your browser.
  6. Choose when Telekom should ask for a code (next section).
  7. Check the summary and confirm with Fortfahren (continue).

Telekom's pages mention only the QR code, not a key to type. If you're offered one, tap +, then Enter key manually in Novaz and enter it as the Setup key (What is a 2FA setup key?). Any app that supports the OTP standard works, according to Telekom (Telekom).

Choose when Telekom asks for a code

The setting Abfrage von Bestätigungscodes (asking for verification codes) has two options (Telekom):

  • Nur bei wichtigen Aktionen (only for important actions): no extra code at sign-in. You need one only for security-related changes, such as a new email address.
  • Bei jeder Anmeldung und bei wichtigen Aktionen (at every sign-in and for important actions): signing in to the Kundencenter or the MeinMagenta app also takes a code.

Telekom recommends the second option. You can change it later under Sicherheit (security) in your login settings, which also shows whether multi-factor authentication is set up. One exception: MagentaTV on some devices can't use it for technical reasons, so there you still sign in with user name and password.

Trusted devices

A sign-in from an unknown device or a new location can trigger extra checks such as a code, and always sends you a notice (Telekom). On your own devices you can skip some checks by choosing Diesem Gerät vertrauen (trust this device) when you sign in. The same page also calls it Auf diesem Gerät nicht mehr fragen, so the label may vary. This needs multi-factor authentication on, a device you've used for at least 24 hours, and a browser that keeps cookies. You can trust up to three devices and remove them under Mein Profil > Login-Einstellungen > Login-Daten > Bekannte Geräte (known devices).

Mail apps use a separate password

Apple Mail, Outlook and Thunderbird don't use your Telekom Login password. They use a Passwort für E-Mail-Programme (password for email programs), set in the Kundencenter under Profil verwalten > Login-Daten > Weitere Passwörter (Telekom). Telekom's multi-factor pages don't mention email programs. The E-Mail Center and the Telekom Mail app do sign in with the Telekom Login (Telekom).

No backup codes

Telekom's help doesn't mention backup or recovery codes. Its setup video says you can keep getting codes by text message after adding an app (Telekom), while the written steps have you pick one method. Check Sicherheit afterwards to see what's set. Unless you've backed up Novaz with iCloud backup or a backup file, its keys exist only on your iPhone, so a current mobile number on your Telekom Login is your fallback.

If Telekom rejects your code

Telekom's troubleshooting page covers text messages that don't arrive, not app codes (Telekom). For an app code, check your iPhone's clock: Settings > General > Date & Time > Set Automatically. Novaz also warns you when the clock is 15 seconds or more off. More causes: Authenticator code not working?

Changing phones

Telekom doesn't describe moving the authenticator. Your multi-factor settings live under Sicherheit, so change them there while you still have the old iPhone and can get a code. If you have a Novaz iCloud backup or backup file, you can restore your accounts on the new iPhone instead and keep the same codes. See How to transfer your authenticator app to a new iPhone.

If you lose your authenticator

Telekom's help doesn't say what to do when the app is gone. What it does cover:

  • If text-message codes are set up too, use one.
  • If the phone was lost or stolen, change your password and other login settings right away, Telekom says (Telekom), and remove it from Bekannte Geräte if you trusted it.
  • Andere Anmeldeoptionen (other sign-in options) checks who you are through your Telekom home Wi-Fi, a security question, a code by email or text, or contract data such as your customer number (Telekom). Telekom describes it for a forgotten user name or password and doesn't say whether it replaces a missing app code.
  • Otherwise, contact Telekom's customer service (Telekom). Its pages don't say what proof it asks for or how long it takes.

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