Why is my new volume that I restored from a snapshot not moving to 'stable' status?

A fully restored volume was not created from the snapshot. The API health status shows degraded, with the health reason initializing_from_snapshot and a message indicates that initializing from the snapshot failed.

Some or all of the data wasn't downloaded from the regional storage repository to the volume that's being created. Data blocks were not written.

Contact IBM support to determine the root cause of the failure and resolve the problem.