Biometric Device Error Code 521 and Possible Solution

The error code 521 indicates "Invalid dc code" - means the device code used for biometric authentication is not valid or not properly registered with the UIDAI; essentially.

Probable reasons are

1. The device is not registered with the UIDAI and Service provider (ACPL or Mantra)

2. The device is blocked by UIDAI due to suspected fraud due suspicious activity

3. The device is unregistered at Service provider end due to frequent change of source systems.

Possible solutions

1. Re registration

2. Write to the service provider for activation