chdir(/var/spool/postfix No such file or directory (but it exists)

I’m trying to set up mail server. I edit main.cf in /etc/postfix … then I try to restart postfix service and this is what I get

fatal: chdir(/var/spool/postfix : No such file or directory


actually it is this variable

queue_directory = /var/spool/postfix 


but that directory exist and couple of subdirs/files in it output of

ls -la /var/spool/postfix


is this

/var/spool/postfix:                                                                                                                                   
total 0                                                                                                                                               
drwxr-xr-x 1 root    root      166 Nov  6 16:36 .                                                                                                     
drwxr-xr-x 1 root    root      138 Jan 20 12:48 ..
drwx------ 1 postfix root        0 Oct 18 15:11 active
drwx------ 1 postfix root        0 Oct 18 15:11 bounce
drwx------ 1 postfix root        0 Oct 18 15:11 corrupt
drwx------ 1 postfix root        0 Oct 18 15:11 defer
drwx------ 1 postfix root        0 Oct 18 15:11 deferred
drwx------ 1 postfix root        0 Oct 18 15:11 flush
drwx------ 1 postfix root        0 Oct 18 15:11 hold
drwx------ 1 postfix root        0 Oct 18 15:11 incoming
drwx-wx--- 1 postfix maildrop 8000 Feb  3 16:29 maildrop
drwxr-xr-x 1 root    root        0 Jan 19 10:06 pid
drwx------ 1 postfix root      200 Jan 19 09:32 private
drwx--x--- 1 postfix maildrop   54 Jan 19 09:32 public
drwx------ 1 postfix root        0 Oct 18 15:11 saved
drwx------ 1 postfix root        0 Oct 18 15:11 trace


and what is in main.cf about that variable

The queue_directory specifies the location of the Postfix queue.
# This is also the root directory of Postfix daemons that run chrooted.
# See the files in examples/chroot-setup for setting up Postfix chroot
# environments on different UNIX systems

so I think it looks OK ??