Common Errors

Unexpected physicalDeviceId

When thrown by any SDK function, this error indicates that the physicalDeviceId associated with the deviceId in Fireblocks and the physicalDeviceId sent with the request are not identical.

The physicalDeviceId is an ID the SDK provisions when the SDK is initialized on a new web browser or mobile device. After the generateMPCKeys function generates key shares or an end user completes the recovery procedure, Fireblocks assigns the deviceId to the physicalDeviceId. This means that the same deviceId cannot issue requests (e.g., sign transactions) from any other SDK initialization.



The SDK initialization occurs with a specific deviceId.

Below are some scenarios that may result in an Unexpected physicalDeviceId exception.

Unexpected physicalDeviceId after recovery

As described here, encrypted key share backups are associated with a corresponding deviceId. When an end-user recovers a key share from a new device (i.e., a different physicalDeviceId than their original device), the deviceId of the original device is no longer associated with the key share.


If Device A (physicalDeviceId: pd1 and deviceId: d1) generates a key share, and Device B (physicalDeviceId: pd2) recovers Device A's key share, the NCW SDK will throw the Unexpected physicalDeviceId error message when Device A attempts to sign a transaction since pd1 is no longer associated with d1.

Unexpected physicalDeviceId after key generation abruptly stopped

During the key generation process, Fireblocks associates the physicalDeviceId with the deviceId. If the process is interrupted and then restarted with the same deviceId but a different physicalDeviceId, the NCW SDK will throw the Unexpected physicalDeviceId error message.


  • Reinstalling the app, clearing the storage, and then calling generateMPCKeys again
  • Calling generateMPCKeys from another device