User can log on to XenServer through serial console, but they cannot access the shell prompt from XenServer.

The "management Service VM missing" error is observed from the output of the following command:
[root@sdx-2 ~]# xe vm-list

uuid ( RO)           : c5c1ea96-2eaf-441c-ac68-c71a6a79192e
name-label ( RW): Control domain on host: netscaler-sdx
power-state ( RO): running
uuid ( RO)           : 3074eee3-1fd4-75f0-1f6b-019ab7acd10e
name-label ( RW): Xen API SDK (1)
power-state ( RO): halted
(management Service VM missing)
[root@sdx-2 ~]# list_domains
id |                                 uuid |  state
0 | c5c1ea96-2eaf-441c-ac68-c71a6a79192e |     R
 [root@sdx-2 ~]# fdisk -l
Disk /dev/sda: 256.0 GB, 256060514304 bytes
255 heads, 63 sectors/track, 31130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1         523     4200966   1c  Hidden W95 FAT32 (LBA)
/dev/sda2   *         524        1046     4194304   83  Linux
/dev/sda3            1046        1568     4194304   83  Linux
/dev/sda4            1568       31130   237462119+  8e  Linux LVM
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdb doesn't contain a valid partition table

To resolve this issue, factory reset the NetScaler SDX appliance.