Troubleshooting Face ID & Touch ID Biometrics

How biometric credentials stored in iOS/Android keychains work and resolving sign-in prompts.

1. What Biometric Sign-In Actually Does

Biometric sign-in in Membrzs Market is a convenience for returning to an account you've already signed into on that device — it is not a way to create a new session from scratch, and it doesn't replace your password entirely.

When you enable it, the app securely stores your session's refresh token in your phone's keychain (iOS Keychain or Android's equivalent secure storage), protected by your device's Face ID, Touch ID, or Android fingerprint/biometric unlock. The next time you open the app, tapping Sign in with Face ID (or Touch ID / Biometrics) unlocks that stored token with a biometric prompt and uses it to restore your session — instead of you typing your password again. Your actual account password is never stored on the device.

2. Enabling Biometric Sign-In

  1. After a normal email/password sign-in, if your device supports Face ID, Touch ID, or fingerprint unlock, you may see a prompt: "Enable Face ID?" — "Sign in faster next time using Face ID instead of your password." Tap Enable.
  2. You can also turn it on any time from Config > Account. If your device supports biometrics, you'll see a Face ID / Touch ID / Biometrics toggle with the description "Unlock the app without entering your password." Switch it on.
  3. Your device will ask you to confirm with Face ID, Touch ID, or your fingerprint before the toggle takes effect.

3. Signing In With Biometrics

On the sign-in screen, if biometrics are enabled, you'll see a Sign in with Face ID (or Touch ID / Biometrics) option below the normal email/password fields. Tap it and complete the biometric prompt to continue.

If you cancel the biometric prompt, the app falls back to normal email/password sign-in — nothing is lost, you just didn't use the shortcut that time.

4. Turning Biometric Sign-In Off

Go to Config > Account and switch the Face ID / Touch ID / Biometrics toggle off. This removes the securely stored session credential from your device; you'll sign in with your email and password (and MFA, if enabled) going forward, until you turn it back on.

5. Troubleshooting Common Issues

  • The toggle doesn't appear at all in Config > Account. Your device doesn't support Face ID/Touch ID/fingerprint unlock, or it hasn't been set up at the operating-system level. Set up Face ID/Touch ID/fingerprint unlock in your phone's system settings first — Membrzs reads that capability from the OS, it doesn't provide its own biometric enrollment.
  • Tapping "Sign in with Face ID" does nothing, or immediately fails. This can happen if your underlying session was fully revoked (for example, after a password reset or a long period without opening the app). Cancel and sign in with your email and password — this automatically re-establishes a valid session, and you can re-enable the biometrics toggle in Config > Account afterward.
  • You get an option to "Use password instead." This is a normal, built-in fallback shown as part of the biometric prompt itself (not an error) — tap it any time you'd rather type your password.
  • You changed or added a new Face ID/fingerprint on your phone. Since the credential is tied to your device's biometric system rather than to a specific fingerprint or face, this generally continues to work; if it stops, turn the toggle off and back on in Config > Account to re-store the credential under the current biometric enrollment.
  • You reinstalled the app or switched phones. Biometric sign-in is stored per device/per install and does not transfer. Sign in normally with your email and password on the new device or fresh install, then re-enable the toggle if you'd like to use it there too.

Frequently Asked Questions

Does biometric sign-in work on both iOS and Android?

Yes. On iOS it uses Face ID or Touch ID depending on your device; on Android it uses your device's supported fingerprint/biometric unlock. The app labels the toggle and buttons accordingly.

Is my fingerprint or face scan sent to Membrzs?

No. Biometric matching happens entirely on your device via the operating system. Membrzs never receives or stores biometric data — only a securely stored session token that's unlocked by your device's own biometric check.

If I share a device with another seller, will biometrics let them into my account?

Biometric sign-in unlocks whichever account most recently enabled it on that device. If multiple people share a device, we recommend each person keep biometrics off and sign in with their own email and password, or sign out fully between shifts.