During migration for the indicated storage pool, a required volume could not be mounted.
The indicated migration process ends. The server waits for the retry period to expire and then tries the migration again. If other migration processes are executing for the named storage pool, these processes will continue migration.
One possible cause for this failure is that the access state for the target volume or storage pool for this operation is not set to READWRITE. Check the access state for the requested output volume and storage pool and ensure they are set to ACCESS=READWRITE.