Is your fingerprint sensor not working? Is it showing an error message? or worse, is the option completely missing from your device? 

No worries, here are some sure-shot solutions to fix the issue at home, especially when the problem is not related to hardware.

1. Check if your fingerprint module has any liquid or dirt. -

First thing first. The fingerprint sensor may not work if your hand is wet, moisty, oily, or dirty. So, if your finger has any of these, clean it, and wait to dry it out.

Just as having a clean finger, the fingerprint module should also be clean. Especially if you used a moisturizer earlier, the module would accumulate liquid from your fingers, causing the sensor not to read your fingers properly. To fix this, kindly check if the fingerprint module has any liquid or dirt and clean it with a dry cloth. 

2. Check that you're using the same finger you used when you enrolled in Fingerprint Unlock.

3. Clear the cache data and reboot your device

4. Update all apps and software system

5. Add a new fingerprint: Go to the Settings app, select "Security", tap on "Fingerprint", and add a new fingerprint.

If you could add another fingerprint, it should be able to unlock your device now.

6. Use your Phone in Safe mode: Try using your phone in SAFE MODE. Is it working fine? then some faulty app is the culprit. In such a case, delete the recently downloaded apps. 

7. Do a Factory Reset: If all above solutions don't work, you can try Factory Reset. But make sure you take data backup, as this technique removes all data from your device. 

8. Check if the fingerprint module is well connected: Is your fingerprint module clickable or shaking? It's likely to be damaged.