Shouldn’t you use a colon (:) instead of a semicolon (;)?
/dev/sdb1 is your block device. What does ls -l show on its mountpoint?
Example:
➜ ~ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 465,8G 0 disk
└─sda1 8:1 0 465,8G 0 part /mnt/ssdsata
<snip>
➜ ~ ls -l /dev/sda1
brw-rw----. 1 root disk 8, 1 lip 27 16:13 /dev/sda1
➜ ~ ls -l /mnt/ssdsata
total 24
drwxrwsr-x+ 2 bifutake adminstorage 16384 ožu 6 00:38 lost+found
If it’s root, you should change it to your username:
sudo chown -R user:group /path_to_your_mountpoint
If you want to leave your group as is, just leave it blank after a colon:
sudo chown -R user: /path_to_your_mountpoint
Put your username instead of user, of course.
