Aadhaar authentication is required everywhere in India today: withdrawing rations (PDS), opening bank accounts, buying SIM cards, transferring property, completing EPF KYC, filing taxes, and even unlocking DigiLocker. When the machine beeps red and says "Authentication Failed," it blocks your access to essential services and leaves you stuck at the counter.
Authentication can fail during any of the four modes: Biometric (fingerprint or iris), Demographic (name/DOB mismatch), OTP, or Face. Each mode fails for different reasons and has different fixes.
If your problem is only missing SMS OTPs, start with Aadhaar OTP not received. If DigiLocker signup fails on Aadhaar verify, see DigiLocker Aadhaar verification failed. To unlock fingerprints for Error 330, use Lock or unlock Aadhaar biometrics.
Quick Diagnosis: Which Error Are You Getting?
| Error / Symptom | Most Likely Cause | Jump To |
|---|---|---|
| Fingerprint scan fails repeatedly | Worn-out or dirty fingerprints | Error 1 below |
| Instant rejection without scanning | Biometrics locked (Error 330) | Error 2 below |
| "Demographic mismatch" or "Name does not match" | Name/DOB difference between Aadhaar and the service | Error 3 below |
| OTP entered but "authentication failed" | Expired OTP or UIDAI server timeout | Error 4 below |
| Face scan fails on phone app | Lighting, glasses, or liveness check failure | Error 5 below |
| "Technical error" or "Service unavailable" | UIDAI server outage | Wait 30-60 min, retry |
Error 1: Fingerprint Mismatch
This is the most common failure. It disproportionately affects manual laborers, senior citizens whose skin has lost elasticity, young children whose prints are still developing, and people with dry or cracked skin.
Causes:
- Worn-out fingerprints due to age, farming, construction work, or household chemicals
- Dirty, sweaty, or excessively dry fingers
- Smudged glass on the fingerprint scanner device itself
- Scanner quality issues at the operator's end
Immediate Solutions (At the Counter):
- Clean the scanner: Ask the operator to wipe the scanner glass with a dry, lint-free cloth. Smudges from previous users cause many failures.
- Clean and dry your hands: Wash thoroughly and dry completely. If your hands are very dry and cracked, apply a tiny amount of moisturizer or hand cream, then wipe off the excess before scanning. This fills in the cracks and improves ridge visibility.
- Try different fingers: You do not have to use the thumb. Try index, middle, or ring fingers. UIDAI captures all 10 fingerprints during enrollment, so any finger should work.
- Press firmly but not too hard: A light touch gives incomplete ridges. Pressing too hard flattens the ridges and distorts the print. Apply moderate, consistent pressure.
- Ask for Iris Scan: If the center has an iris scanner (most banks and government offices do), ask them to switch to iris authentication. Iris patterns do not wear out like fingerprints and have a much higher success rate.
Permanent Solution: If your fingerprints fail consistently across multiple visits, you must visit an Aadhaar Seva Kendra and request a Biometric Update (fee: Rs 100). The operator will capture fresh scans of all 10 fingers, both irises, and a new photograph. It takes 2-5 days for the new biometrics to propagate across UIDAI servers.
TIP
For manual laborers and farmers: After getting a biometric update, switch to iris-based authentication for all future verifications wherever possible. Iris patterns remain stable throughout your life, while fingerprints continue to deteriorate with manual work.
Error 2: Biometrics Locked (Error Code 330)
If the machine instantly rejects the scan without even attempting to match it, or if you receive a message saying "Biometric data locked" or "Error 330," your biometrics are locked. This is a UIDAI security feature to prevent identity theft.
Why it might be locked:
- You locked it yourself for security (recommended practice when not actively using Aadhaar services)
- A family member locked it from the mAadhaar app
- It was auto-locked after a suspicious authentication attempt
How to Fix It:
- Open the mAadhaar app on your smartphone or visit myaadhaar.uidai.gov.in.
- Log in using your Aadhaar number and OTP.
- Navigate to the Lock/Unlock Biometrics section.
- Click Unlock. You will see two options:
- Temporary Unlock (10 minutes): Biometrics are unlocked for 10 minutes and then automatically re-lock. Use this if you need to authenticate once and want to keep them locked afterward.
- Permanent Unlock: Biometrics remain unlocked until you explicitly lock them again.
- Wait 5-10 minutes after unlocking, then try the fingerprint or iris scan again.
See our complete guide on Aadhaar Biometric Locking for detailed steps.
IMPORTANT
Best practice: Keep your biometrics locked when you are not using Aadhaar services. This prevents anyone from authenticating as you (e.g., fraudulent SIM activations or bank transactions). Unlock temporarily only when needed.
Error 3: Demographic Data Mismatch
This happens when you are trying to link Aadhaar to another service (EPF, Income Tax, bank, DigiLocker), and the details you provided to that service do not match what is in UIDAI's database.
Common mismatches:
| Your Input | What Aadhaar Has | Result |
|---|---|---|
| "Ramesh Kumar" | "Ramesh K" | Fails |
| DOB: 15/06/1990 | DOB: 1990 (year only) | May fail |
| Gender: Male | Gender: Female (data entry error) | Fails |
| "Mohammed" | "Mohammad" | Fails |
How to fix:
- Download your e-Aadhaar from myaadhaar.uidai.gov.in and check the exact name, DOB, and gender.
- Determine which document is wrong. If Aadhaar has an error, update it online (for address, email, mobile) or at an Aadhaar center (for name, DOB, gender, biometrics).
- If the other service has the error (e.g., your EPF record says "R Kumar" but Aadhaar says "Rajesh Kumar"), update the details at that service provider. For EPF, this requires a Joint Declaration Form signed by your employer.
- For partial DOB issues: If your Aadhaar only records the year of birth (common for older Aadhaar holders), check the "Only Year of Birth" box when linking. Most portals have this option but it is easy to miss.
Error 4: OTP Authentication Failed
If you enter the OTP but the portal says "authentication failed":
Causes:
- You took too long to enter it (OTPs expire exactly 10 minutes after generation)
- You entered an older OTP after requesting multiple times. UIDAI always invalidates the previous OTP when a new one is sent. Only the most recent OTP works.
- Network timeout between the application and UIDAI servers
- UIDAI server overload during peak hours
How to fix:
- Wait 15-30 minutes, then refresh the page completely.
- Request a single fresh OTP and enter it immediately. Do not request multiple OTPs in rapid succession.
- If OTPs are consistently not arriving, use TOTP from the mAadhaar app as an alternative (see our OTP troubleshooting guide).
- Try during off-peak hours: early morning (6-8 AM) or late evening (8-11 PM).
Error 5: Face Authentication Failed
UIDAI's Face Authentication (via the Aadhaar FaceRD app on smartphones) is used for services like Jeevan Pramaan (life certificate for pensioners), PM-Kisan, and some banking verifications.
Causes and fixes:
| Cause | Fix |
|---|---|
| Poor lighting | Position yourself facing a window or bright light. The light source should be in front of you, not behind you. |
| Blurry camera lens | Clean the phone's front camera lens with a soft cloth |
| Wearing glasses | Remove glasses entirely before scanning |
| Wearing hat, mask, or scarf | Remove any head or face coverings |
| Not blinking when prompted | The app requires a blink to verify "liveness" (proving you are real, not a photo). Blink naturally when the app prompts you. |
| Old Aadhaar photo does not match current face | If you look significantly different from your Aadhaar photo (weight change, ageing, surgery), get a biometric update (Rs 100) at an Aadhaar Seva Kendra to update your photo. |
What if a Senior Citizen's Biometrics Just Won't Match?
For very elderly individuals, fingerprints may fade completely due to age, and cataracts or eye surgeries can interfere with iris scans, making biometric authentication nearly impossible even after updates.
In such cases:
- Use OTP authentication wherever possible. Most services accept OTP as an alternative to biometrics.
- For banking: Submit physical KYC documents with a signature or thumb impression attested by a gazetted officer or branch manager, rather than relying on AEPS (Aadhaar Enabled Payment System) or eKYC.
- For government pensions/schemes: Authorities often have manual override procedures called "authentication exceptions" where a physical verification by a designated officer replaces the biometric requirement. Ask the respective department for their exception protocol.
- For PDS rations: If biometrics consistently fail at the ration shop, your district food officer can flag your Aadhaar for manual distribution.
UIDAI Error Codes Reference
| Error Code | Meaning | Quick Fix |
|---|---|---|
| 300 | Biometric data did not match | Clean scanner, try different finger, or get biometric update |
| 330 | Biometrics are locked | Unlock via mAadhaar app or MyAadhaar portal |
| 400 | Invalid Aadhaar number | Check for typos in the 12-digit number |
| 500 | Aadhaar number not found in UIDAI database | Very rare; contact UIDAI helpline at 1947 |
| 510 | Invalid OTP | Request a fresh OTP and enter immediately |
| 520 | OTP expired | OTPs are valid for 10 minutes only; request a new one |
| 940/941 | Technical error at UIDAI | Server issue; wait and retry later |
| 998 | Request limit exceeded | Too many attempts; wait 24 hours |
Related Guides
- How to Lock or Unlock Aadhaar Biometrics
- Aadhaar OTP Not Received: How to Fix It
- How to Update Mobile Number on Aadhaar
- DigiLocker Aadhaar Verification Failed
Need more help?
For more information, open the Aadhaar Help hub, browse Identity & KYC guides, or try our calculators.