Start up userApplication and see if it is normally running on all nodes.
NAS device
Check if a volume is mounted on an operating node. You also need to check if the file can be read and written.
Point
For further detailed information on how to verify that NAS is mounted and accessed from the node, refer to "Chapter 5 Notice".
If it is not normally running, take corrective action referring to "3.1 Corrective action during failover".