Guys, I have an SSD which I connect via usb.
It apparently mounts and shows me the directories inside it.
Only it won't let me write in it anymore.
When I run the command:

sudo lsblk -o NAME,TYPE,FSTYPE,SIZE,LABEL,UUID,MOUNTPOINT
Eu obtenho o seguinte
NAME TYPE FSTYPE SIZE LABEL UUID MOUNTPOINT
loop0 loop squashfs 4K /snap/bare/5
loop1 loop squashfs 114.9M /snap/core/13741
loop2 loop squashfs 115M /snap/core/13886
loop3 loop squashfs 62M /snap/core20/1611
loop4 loop squashfs 63.2M /snap/core20/1623
loop5 loop squashfs 389.7M /snap/qt515-core20/25
loop6 loop squashfs 864K /snap/glate/24
loop7 loop squashfs 91.7M /snap/gtk-common-themes/1535
sda disk 119.2G
├─sda1 part vfat 476M 1657-EAC9 /boot/efi
├─sda2 part swap 7.5G dfbbfaff-33f4-4ca8-b9a8-1a55c779cdcd [SWAP]
└─sda3 part ext4 111.3G 72b3e670-264e-4ac3-bd72-d87f0d994a28 /
sdb disk 931.5G
├─sdb1 part ext4 465.7G 304bf668-1d3d-4eab-b1b5-8e9b9b784676 /home
└─sdb2 part vfat 465.9G 1619-561E /windows
sdc disk 465.8G
├─sdc1 part vfat 475.9M EFB2-F4F9
├─sdc2 part vfat 334G SAMSUNG_FAT F371-A281 /media/nogueira/SAMSUNG_FAT
├─sdc3 part ext4 130.8G HD_Externo_M3 7a59695c-7ca8-463a-9699-f24c77e1c507 /media/nogueira/HD_Externo_M3
└─sdc4 part swap 500M 41aedc32-07b2-4831-a0f7-6f6be98bcd6f
sdd disk 465.8G
├─sdd1 part vfat 475.9M 5BFE-8B2F
├─sdd2 part ext4 147G 49f3d240-a3f5-43ae-b794-efcfbeecfa83 /media/nogueira/49f3d240-a3f5-43ae-b794-efcfbeecfa83
├─sdd3 part swap 8.8G f8875c75-d0d3-4c21-8bc5-97d38f5a7c6c
└─sdd4 part ext4 309.5G Timeshift 22753fc7-e83a-46d0-800d-2daf44a994d6 /media/nogueira/Timeshift
sde disk 1.9T
└─sde1 part vfat 1.9T SSD 3D2C-AF31 /media/nogueira/SSD
mmcblk0 disk 1.9G
└─mmcblk0p1 part vfat 1.9G 1711-59D4 /media/nogueira/1711-59D4

But when I go to check fstab it doesn't show up there:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda3 during installation
UUID=72b3e670-264e-4ac3-bd72-d87f0d994a28 / ext4 noatime,errors=remount-ro 0 1
# /boot/efi was on /dev/sda1 during installation
UUID=1657-EAC9 /boot/efi vfat umask=0077 0 1
# /home was on /dev/sdb1 during installation
UUID=304bf668-1d3d-4eab-b1b5-8e9b9b784676 /home ext4 noatime,defaults 0 2
# /windows was on /dev/sdb2 during installation
UUID=1619-561E /windows vfat utf8,umask=007,gid=46 0 1
# swap was on /dev/sda2 during installation
UUID=dfbbfaff-33f4-4ca8-b9a8-1a55c779cdcd none swap sw 0 0

Even if I try to mount it with the command:

nogueira@Nitro5:~$ sudo mount /dev/sde1 /media/nogueira/SSD
mount: /media/nogueira/SSD: /dev/sde1 already mounted in /media/nogueira/SSD.

It informs me that the directory is already mounted in /media/nogueira/SSD

How could i solve this?

I Thank in advance for any help.

What is the output of

when run against that partition?

It will not show there. You are confused about fstab. I suggest you read about fstab; search for it.

Your external disk automounts, probably with the file manager, therefore you do not need to issue the mount command.

Edit. Try to use code tags for the output of your commands you are posting.

Possibly a permission problem, not owned by your user account, therefore, if you use sudo (or the root account) you can write to it - you will need to alter the permissions to your user account, if you want to write to it regularly.

Sometimes a pendrive just does that. It happened to me recently; an old drive that I've used for a long time for miscellaneous file dumps suddenly couldn't be mounted r/w on either of my machines. Even "sudo mount -o remount,rw" didn't work. Google says that these drives protect themselves when they can't be written to safely any more.

Is your drive an old one? Have you been using it intensively?