WD external HDD not recognized on new mac

Possibly related to this.

Since last Sequoia update (15.1.1 on Macbook M1 Max Pro) , my WD external 260D HDD is no longer recognised by Time Machine. On connection , a popup error message appears 'The disk "TimeMachine" can't be Unlocked. A problem was detected with the disk, which prevents it from being unlocked'

Disk Utility shows the device present with the APFS Container, but will not mount the TimeMachine volume. Attempts to do so result in the above message being repeated. The volume is formatted as APFS Case-sensitive Encrypted. The Container shows 1.25TB/4TB used. 2.75TB free.

The WD Drive Utilities software can access the drive and reports it is in perfect working order.

Is the harddrive formatted the right way? You want to have it formatted in either macOS journaled or APFS