NetApp volume: unknown state (missing volume on GUI)

I ran into an issue recently where the NetApp volume was not visible on the GUI. The system manager reported that aggregates were offline. However, that wasnt really the case. The volume was visible on the command line and an attempt to offline the volume produced the following error :

Modification not permitted. Unable to determine the state of the volume.
  

Issue: This was an issue in synchronizing data between WAFL and VLDB . 

Fix:  Run the 'debug vreport show' command in diagnostic mode. and then run 'debug vreport fix' to fix the error 

Here is the command output

CLUST::*> debug vreport show
aggregate Differences:

Name             Reason   Attributes
--------         -------  ---------------------------------------------------
<Volume Name>
                 Present both in VLDB and WAFL with differences
                          Node Name: Node1
                          Aggregate UUID: AggrgID
                          Aggregate State: online
                          Aggregate Raid Status: mixed_raid_type, hybrid
                          Aggregate HA Policy: sfo
                          Is Aggregate Root: false
  Differing Attribute: Volume Count (Try to fix volume differences using vreport for volume, and check again.)
    WAFL Value: 18
    VLDB Value: 19

volume Differences:

Name             Reason   Attributes
--------         -------  ---------------------------------------------------
VserverName:Volume Name
                 Present in VLDB Only
                          Node Name: Node1
                          Volume DSID:xxx MSID:yyyy
                          UUID: unknown
                          Aggregate Name: AggrName
                          Aggregate UUID: xxxx
                          Vserver UUID: xxxx
                          AccessType: READ_WRITE
                          StorageType: CLONE
                          Constituent Role: none

2 entries were displayed.
 

CLUST::*> debug vreport fix -type volume -object SFM:Volume_CVclone