/boot/efi unable to mount

In our physical box, we have installed SLES 12SP3. After reboot we are unable to boot the server. It was unable to mount /boot/efi. We checked the system and observe a strange things. When we try to mount /dev/sda1 to /boot/efi, it dose not give any error, but it dose not mounted. When we try to mount /dev/sda1 in some other location (i.e. /mnt), it was successfuly mounted.

Can you show the output from the following to provide additional information;

cat /etc/os-release
cat /etc/fstab
efibootmgr -v