Server Stuck on grub terminal

After upgrade REHL 6 to 7 and rebooting the server which is implemented on HP Gen9 a grub terminal show up and I can't boot up the os .

Do you have any clue how to solve this issue without loss the data which was implemented on this server.

grub> reboot
HP ProLiant System BIOS P89 v2.00 (12/27/2015)
(C) Copyright 1982 - 2015 Hewlett Packard Enterprise Development LP
Early system initialization, please wait...

iLO 4 IPv4: 10.28.20.103
iLO 4 IPv6: FE80::1E98:ECFF:FE23:60D2

2%: System Chipset Initialization
4%: QPI Link Initialization - Start
6%: QPI Link Initialization - Complete
9%: Early Processor Initialization
11%: Memory Initialization - Start
21%: Memory Initialization - Complete

24%: System Security Initialization
27%: HPE SmartMemory Initialization
37%: Loading System Firmware Modules - Start
46%: Loading System Firmware Modules - Complete
49%: USB Controller Initialization
52%: Chipset Root Ports Initialization
55%: Processor Root Ports Initialization
61%: ACPI Table Initialization

64%: SMBIOS Table Initialization
67%: iLO Embedded Health Initialization
70%: BIOS Configuration Initialization
76%: Early PCI Initialization - Start
82%: Early PCI Initialization - Complete
91%: Switching console output to Primary Video. Please wait..

grub>
grub> ls
(hd0) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (lvm/VolGroup-lv_root)
(lvm/VolGroup-lv_swap) (lvm/VolGroup-lv_home) (lvm/VolGroup-lv_varlog)
(lvm/VolGroup-lv_var) (lvm/VolGroup-lv_vartmp) (lvm/VolGroup-lv_varlogaudit)
(lvm/VolGroup-lv_varlog_altroot) (lvm/VolGroup-lv_swap_altroot)
(lvm/VolGroup-lv_root_altroot)