mount(2) system call failed: File exists.

$ sudo mount /dev/2TB/backup /media/backup
mount: /media/backup: mount(2) system call failed: File exists.
$ sudo mkdir /media/new-dir
$ sudo mount /dev/2TB/backup /media/new-dir
mount: /media/new-dir: mount(2) system call failed: File exists.
$ lsblk
NAME                   MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                      8:0    0 238.5G  0 disk
├─sda1                   8:1    0   230M  0 part  /mnt/esp
└─sda2                   8:2    0 238.3G  0 part
  └─crypt              254:0    0 238.3G  0 crypt
    ├─vg_svelte-home   254:1    0   201G  0 lvm   /mnt/btrfs-vol/home
    ├─vg_svelte-swap   254:2    0  12.3G  0 lvm   [SWAP]
    └─vg_svelte-rootfs 254:3    0    25G  0 lvm   /mnt/btrfs-vol/rootfs
sdb                      8:16   0   1.8T  0 disk
├─sdb1                   8:17   0   693G  0 part
├─sdb2                   8:18   0   663G  0 part
│ ├─2TB-backup         254:4    0   1.1T  0 lvm
│ └─2TB-spare          254:5    0    50G  0 lvm
└─sdb3                   8:19   0   507G  0 part
  └─2TB-backup         254:4    0   1.1T  0 lvm
$