Cannot logon by GUI

Hello everyone.
I use Raspberry PI 3 + OMV v3.x +(nginx Nextcloud)
Everything works fine until yesterday when by OMV GUI I cannot login it just nothing happening.
When I put wrong user name or password there is prompt communitat but when I put correct user/password it już thinking several seconds and back to login page.
The same problem there is with Nextcloud I try to login by standard user or by admin but it the same problem just nothing happens.
Only SSH connection work.

root@malinkapi:/# du -d1 -h
1,9M ./home
19M ./run
8,5M ./etc
9,5M ./boot.bak
0 ./dev
16K ./lost+found
404M ./media
0 ./sys
64K ./root
24K ./tmp
22M ./boot
2,9G ./var
93G ./srv
4,0K ./export
42M ./opt
7,9M ./bin
1003M ./usr
15M ./sbin
0 ./proc
374M ./lib
4,0K ./mnt
97G .

Now I try login again but still I cannot.
I try another accounts but the same problem.

Ok I see that there is problem with one of partition
What can I delete.

root@malinkapi:/# df -h
File system Size Used Avail Use% Mounted on
/dev/root 4,4G 4,4G 0 100% /
devtmpfs 481M 0 481M 0% /dev
tmpfs 486M 0 486M 0% /dev/shm
tmpfs 486M 20M 467M 4% /run
tmpfs 5,0M 4,0K 5,0M 1% /run/lock
tmpfs 486M 0 486M 0% /sys/fs/cgroup
/dev/mmcblk0p1 56M 22M 35M 39% /boot
/dev/mmcblk0p3 24G 395M 23G 2% /media/fa36508a-b3c4-4499-b30a-711dd5994225
/dev/sda1 230G 93G 126G 43% /srv/dev-disk-by-id-usb-SAMSUNG_HM250HJ_321DA10A101917-0-0-part1
tmpfs 98M 0 98M 0% /run/user/0

Thank you very much.
I forgot that few days earlier I tested motion and forgot to stop demon.
Motion make many pictures and filled whole partition.