When the Offline authentication succeed, I observe the following krb5_child.log :
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [main] (0x0400): krb5_child started.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [unpack_buffer] (0x1000): total buffer size: [160]
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [unpack_buffer] (0x0100): cmd [241] uid [1000] gid [1000] validate [true] enterprise principal [false] offline [true] UPN [cedric@ECCM.LAN]
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [unpack_buffer] (0x0100): ccname: [FILE:/var/tmp/krb5cc_1000_XXXXXX] old_ccname: [FILE:/var/tmp/krb5cc_1000_vbmc1v] keytab: [/etc/krb5.keytab]
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [check_use_fast] (0x0100): Not using FAST.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [switch_creds] (0x0200): Switch user to [1000][1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [switch_creds] (0x0200): Switch user to [0][0].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [k5c_check_old_ccache] (0x4000): Ccache_file is [FILE:/var/tmp/krb5cc_1000_vbmc1v] and is active and TGT is valid.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [privileged_krb5_setup] (0x0080): Cannot open the PAC responder socket
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [become_user] (0x0200): Trying to become user [1000][1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [main] (0x2000): Running as [1000][1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [become_user] (0x0200): Trying to become user [1000][1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [become_user] (0x0200): Already user [1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [k5c_setup] (0x2000): Running as [1000][1000].
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [set_lifetime_options] (0x0100): No specific renewable lifetime requested.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [set_lifetime_options] (0x0100): No specific lifetime requested.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [main] (0x0400): Will perform offline auth
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [create_empty_ccache] (0x1000): Existing ccache still valid, reusing
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [k5c_send_data] (0x0200): Received error code 0
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [pack_response_packet] (0x2000): response packet size: [56]
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [k5c_send_data] (0x4000): Response sent.
(Tue May 1 13:17:16 2018) [[sssd[krb5_child[10318]]]] [main] (0x0400): krb5_child completed successfully
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [fo_resolve_service_send] (0x0020): No available servers for service 'KERBEROS'
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_resolve_server_done] (0x1000): Server resolution failed: [5]: Erreur d'entrée/sortie
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_mark_dom_offline] (0x1000): Marking back end offline
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_mark_offline] (0x2000): Going offline!
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_mark_offline] (0x2000): Enable check_if_online_ptask.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_ptask_enable] (0x0400): Task [Check if online (periodic)]: enabling task
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_ptask_schedule] (0x0400): Task [Check if online (periodic)]: scheduling task 80 seconds from now [1525174023]
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [be_run_offline_cb] (0x0080): Going offline. Running callbacks.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [child_handler_setup] (0x2000): Setting up signal handler up for pid [10471]
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [child_handler_setup] (0x2000): Signal handler set up for pid [10471]
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [write_pipe_handler] (0x0400): All data has been sent!
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [read_pipe_handler] (0x0400): EOF received, client finished
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [parse_krb5_child_response] (0x1000): child response [0][3][44].
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [krb5_mod_ccname] (0x4000): Save ccname [FILE:/var/tmp/krb5cc_1000_vbmc1v] for user [cedric@eccm.lan].
....
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [sysdb_set_entry_attr] (0x0200): Entry [name=cedric@eccm.lan,cn=users,cn=ECCM.LAN,cn=sysdb] has set [ts_cache] attrs.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [check_failed_login_attempts] (0x4000): Failed login attempts [0], allowed failed login attempts [0], failed login delay [5].
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [sysdb_cache_auth] (0x0100): Hashes do match!
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [ldb] (0x4000): commit ldb transaction (nesting: 0)
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [add_user_to_delayed_online_authentication] (0x4000): Saved authtok of user [cedric@eccm.lan] with serial [184462369].
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [add_user_to_delayed_online_authentication] (0x4000): Added user [cedric@eccm.lan] successfully to delayed online authentication.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [check_wait_queue] (0x1000): Wait queue for user [cedric@eccm.lan] is empty.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [krb5_auth_queue_done] (0x1000): krb5_auth_queue request [0x55ffb8dee140] done.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [authenticate_user_done] (0x0020): Failed to authenticate user [cedric@eccm.lan].
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [child_sig_handler] (0x1000): Waiting for child [10471].
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [child_sig_handler] (0x0100): child [10471] finished successfully.
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [remove_krb5_info_files] (0x0200): Could not remove [/var/lib/sss/pubconf/kdcinfo.ECCM.LAN], [2][Aucun fichier ou dossier de ce type]
(Tue May 1 13:25:43 2018) [sssd[be[ECCM.LAN]]] [remove_krb5_info_files] (0x0200): Could not remove [/var/lib/sss/pubconf/kpasswdinfo.ECCM.LAN], [2][Aucun fichier ou dossier de ce type]
Thanks a lot for your help.
Regards
Cedric