It depends on your specific use case and application, but in general :
- The address must be unique.
- The address must be random.
- The address must be valid (following the format specified by the Bluetooth SIG).
- The address must be non-resolvable.
- The address must be public or private.
- The address must be unique within a network.
- The address must be easy to remember.
I think you need to check the device's advertising configuration, the unique address and its type (public or private), the RF part if it's correct, etc.
