Thank you for your answer. The file gpo_child is empty :

root@gtw-template:/var/log/sssd# ls -ltr
total 14656
-rw------- 1 root root        0 Apr 19 21:44 gpo_child.log
-rw------- 1 root root     3050 Apr 19 23:16 sssd_pam.log
-rw------- 1 root root     3050 Apr 19 23:16 sssd_nss.log
-rw------- 1 root root    21970 Apr 19 23:22 sssd.log
-rw------- 1 root root    49771 Apr 19 23:22 ldap_child.log
-rw------- 1 root root   112878 Apr 19 23:22 krb5_child.log
-rw------- 1 root root 14800060 Apr 20 00:33 sssd_hq.mydc.com.log