problem of slowness

This log file for today:

2017-10-04 10:36:56.825 ===== TRACE ===== NEW CONNECTED USER 'jop'
2017-10-04 10:54:13.633 ===== TRACE ===== NEW CONNECTED USER 'fca'
2017-10-04 11:03:43.805 ===== TRACE ===== NEW CONNECTED USER 'par'
2017-10-04 11:07:04.536 ***** ERROR ***** [V6.4.1] ERROR *****
2017-10-04 11:07:04.536 ***** ERROR ***** [V6.4.1] on file '/var/www/projeqtor/view/objectStream.php' at line (38)
2017-10-04 11:07:04.536 ***** ERROR ***** [V6.4.1] cause = Undefined property: Work::$idle
2017-10-04 11:07:04.900 ***** ERROR ***** [V6.4.1] ERROR *****
2017-10-04 11:07:04.900 ***** ERROR ***** [V6.4.1] on file '/var/www/projeqtor/tool/jsonQuery.php' at line (691)
2017-10-04 11:07:04.901 ***** ERROR ***** [V6.4.1] cause = Undefined variable: dateWeekOrMonthOrYear
2017-10-04 11:09:08.827 ***** ERROR ***** [V6.4.1] ERROR *****
2017-10-04 11:09:08.827 ***** ERROR ***** [V6.4.1] on file '/var/www/projeqtor/view/objectStream.php' at line (38)
2017-10-04 11:09:08.827 ***** ERROR ***** [V6.4.1] cause = Undefined property: Work::$idle
2017-10-04 11:09:09.137 ***** ERROR ***** [V6.4.1] ERROR *****
2017-10-04 11:09:09.137 ***** ERROR ***** [V6.4.1] on file '/var/www/projeqtor/tool/jsonQuery.php' at line (691)
2017-10-04 11:09:09.137 ***** ERROR ***** [V6.4.1] cause = Undefined variable: dateWeekOrMonthOrYear
2017-10-04 11:25:17.807 ===== TRACE ===== DISCONNECTED USER 'pma'
2017-10-04 11:25:23.871 ===== TRACE ===== NEW CONNECTED USER 'pma'

this is Global parameter for Email:

Log file Yesterday:

2017-10-03 14:47:45.586 ===== TRACE ===== Login error for user ''
2017-10-03 14:47:47.476 ===== TRACE ===== NEW CONNECTED USER 'JRI'
2017-10-03 14:47:58.589 ===== TRACE ===== DISCONNECTED USER 'dep'
2017-10-03 15:01:30.033 ===== TRACE ===== NEW CONNECTED USER 'dep'
2017-10-03 15:01:35.433 ===== TRACE ===== Cron started at 03/10/2017 15:01:35
2017-10-03 15:22:08.501 ===== TRACE ===== NEW CONNECTED USER 'GKR'
2017-10-03 15:31:54.308 ===== TRACE ===== DISCONNECTED USER 'dep'
2017-10-03 15:31:58.725 ===== TRACE ===== NEW CONNECTED USER 'dep'
2017-10-03 15:35:53.645 ===== TRACE ===== NEW CONNECTED USER 'sba'
2017-10-03 15:39:06.642 ===== TRACE ===== NEW CONNECTED USER 'ASE'
2017-10-03 15:42:34.856 ===== TRACE ===== DISCONNECTED USER 'ASE'
2017-10-03 15:42:54.157 ===== TRACE ===== NEW CONNECTED USER 'LOL'
2017-10-03 15:42:59.472 ===== TRACE ===== Cron started at 03/10/2017 15:42:59
2017-10-03 15:48:15.952 ===== TRACE ===== DISCONNECTED USER 'sba'
2017-10-03 15:56:25.712 ===== TRACE ===== NEW CONNECTED USER 'msi'
2017-10-03 16:23:49.979 ===== TRACE ===== DISCONNECTED USER 'dep'
2017-10-03 16:23:52.444 ===== TRACE ===== NEW CONNECTED USER 'dep'
2017-10-03 16:25:45.836 ***** ERROR ***** [V6.4.1] save Data to session : Invalid id value - [displayByStatusList_Activity]
2017-10-03 16:27:08.911 ***** ERROR ***** [V6.4.1] save Data to session : Invalid id value - [displayByStatusList_Activity]
2017-10-03 17:13:31.122 ===== TRACE ===== Logfile->purge() : Technical trace to keep current log file
2017-10-03 17:49:17.839 ===== TRACE ===== NEW CONNECTED USER 'ASE'
2017-10-03 18:06:02.222 ===== TRACE ===== DISCONNECTED USER 'ASE'
2017-10-03 19:09:52.224 ===== TRACE ===== DISCONNECTED USER 'dep'
2017-10-03 19:20:58.401 ===== TRACE ===== DISCONNECTED USER 'jop'

so, I erase cache of my browser.
I deleted all fields of mail in global parameter.

on activity created, I just put 8h on assignment and push record button, it's take 40s.