CBR4108I Unable to determine external volser of mounted volume.

Explanation
 An error has been detected during Library Automation
Communication Services (LACS) processing for the VERIFY function.
The external volume serial number of the volume that is currently
mounted on the requested drive is not recorded in the LACS tables
and cannot be retrieved from the library. Without the external volser,
mount verification cannot be performed.

System action
 The LACS request fails with a permanent error
return code. Messages issued by the caller of LACS are written concurrently
with this message.

Operator response
 The preceding message CBR4000I provides the
device number of the drive on which the volume is mounted. Use the MVS™ VARY command to vary the drive
offline on the system where the error occurred. This will demount
the volume which is mounted on the drive. Then vary the drive back
online.

Source
 Object Access Method (OAM)

Routing Code
 Set by the caller.

Descriptor Code
 Set by the caller.