Odroid xu4 Cloudshell 2 migration problem

Hello!
Just bought the cloudshell 2 and I’m having problems mounting the disks (or maybe I’m not doing it right because I’m a beginner with linux).
I have 2 HDD. One is 3 TB formated ext4 and another one is 2GB formated NTFS.
Before they were connected USB with a USB hub
OS is Dietpi
I set the cloudshell to PM(OFF, OFF) and install Dieti from scratch.
The thing is that I have a full backup(Dietpi with owncloud, plex etc) on the 3TB of my system and I cannot acces it.
Before my disks were mounted automatically in /mnt/cd99a3fb-9b11-447a-b9e2-f0fc668eb05f (3 tb) and /mnt/DC666A53666A2F08 (2TB).
Now:
fdisk -l command:

fdisk -l

Disk /dev/mmcblk0: 14.9 GiB, 15931539456 bytes, 31116288 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x000f1766

Device         Boot  Start      End  Sectors  Size Id Type
/dev/mmcblk0p1        2048   147455   145408   71M  e W95 FAT16 (LBA)
/dev/mmcblk0p2      147456 31116287 30968832 14.8G 83 Linux

Disk /dev/sdb: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x90b8545c

Device     Boot Start       End   Sectors   Size Id Type
/dev/sdb1  *     2048 488378644 488376597 232.9G  7 HPFS/NTFS/exFAT

GPT PMBR size mismatch (732566645 != 1565565871) will be corrected by w(rite).

Disk /dev/sda: 2.7 TiB, 3000592982016 bytes, 5860533168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start       End   Sectors   Size Id Type
/dev/sda1           1 732566645 732566645 349.3G ee GPT



blkid
/dev/mmcblk0p1: SEC_TYPE="msdos" LABEL="boot" UUID="5886-8548" TYPE="vfat" PARTUUID="000f1766-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="a4f12232-1670-43f4-8eca-49bfbe4d01ee" TYPE="ext4" PARTUUID="000f1766-02"
/dev/mmcblk0: PTUUID="000f1766" PTTYPE="dos"
/dev/sdb1: PARTUUID="90b8545c-01"
/dev/sda: PTTYPE="PMBR"

I tried to recreate that folder in mnt for the 3TB drive so I can restore my backup:
cd /mnt/
sudo mkdir cd99a3fb-9b11-447a-b9e2-f0fc668eb05f
sudo chmod 777 cd99a3fb-9b11-447a-b9e2-f0fc668eb05f
sudo mount /dev/sda /mnt/cd99a3fb-9b11-447a-b9e2-f0fc668eb05f
but I get:

wrong fs type, bad option, bad superblock on /dev/sda,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

What is :

GPT PMBR size mismatch (732566645 != 1565565871) will be corrected by w(rite).

What I’m doing wrong? Please help me with this I really need that backup

Now it works. Thanks