Problem with sessions path, owner and permission ?

I think I have problems with sessions path, owner and permission.
I "just installed" OLS with php 7.4.
I did : "$ apt-get install -y lsphp74 lsphp74-common lsphp74-mysql"

OLS Server configuration :
"Server Process - Running As user(nobody) : group(nogroup)"

php.ini :
open_basedir =/var/myhost/php
open_basedir =/var/myhost/php
display_errors = On
display_startup_errors = On
include_path =/var/myhost/php
doc_root =/var/myhost/php
upload_tmp_dir = /var/myhost/php/tmp
session.save_path = /var/myhost/php/tmp/sessions
session.cookie_path = /var/myhost/php/tmp/cookies

$ ps aux :
root openlitespeed (lshttpd - main)
root openlitespeed (lscgid)
nobody openlitespeed (lshttpd - #01)
nobody lsphp
nobody lsphp

I tried this without success :
chown -R lsadm:nogroup /var/myhost/php/tmp/sessions
chown -R root:root /var/myhost/php/tmp/sessions
chown -R nobody:nogroup /var/myhost/php/tmp/sessions

chmod -R 777 /var/myhost/php/tmp/sessions

And when I make this test :

I've got this error :
"session_start(): open(/var/myhost/php/tmp/sessions/sess_1vIqI,[...], O_RDWR) failed: Permission denied (13) in /var/myhost/php/ on line 2 Warning: session_start(): Failed to read session data: files (path: /var/myhost/php/tmp/sessions) in /var/myhost/php/ on line 2"

Any idea ?