Possibly some error.
Please report any error in log file.

the last log file:
2018-09-11 07:56:13.013 ===== TRACE ===== NEW CONNECTED USER 'LOL'
2018-09-11 08:24:34.106 ===== TRACE ===== Login error for user 'jop'
2018-09-11 08:24:41.690 ===== TRACE ===== NEW CONNECTED USER 'jop'
2018-09-11 09:01:09.030 ===== TRACE ===== NEW CONNECTED USER 'par'
2018-09-11 09:02:22.790 ===== TRACE ===== NEW CONNECTED USER 'fch'
2018-09-11 09:06:51.352 ===== TRACE ===== NEW CONNECTED USER 'sba'
2018-09-11 09:10:20.079 ===== TRACE ===== sendMailIfMailable : Mails without dest
2018-09-11 09:11:00.722 ===== TRACE ===== DISCONNECTED USER 'fch'
2018-09-11 09:11:13.523 ===== TRACE ===== NEW CONNECTED USER 'fch'
2018-09-11 09:17:27.728 ===== TRACE ===== NEW CONNECTED USER 'JSD' (using remember me feature)
2018-09-11 09:29:07.977 ===== TRACE ===== DISCONNECTED USER 'JSD'
2018-09-11 10:35:59.526 ===== TRACE ===== NEW CONNECTED USER 'dep'
2018-09-11 10:38:36.750 ===== TRACE ===== Cron started at 11/09/2018 10:38:36
2018-09-11 10:38:44.729 ===== TRACE ===== BackupDatabase has been done by the Cron
2018-09-11 10:38:44.839 ===== TRACE ===== Calcul automatique du planning : calcul différentiel - Projets : 3,5,20,33,67,68,80,87,93,124,144,184,185,187,188,197,225,234,235,237,240,292,348,349,350,363,364,376,380,381,392,421,425,428,432,433,435,437,457,458,460,462,466,467,468,469,473,476,477,479,480,481,482,483,484,489,490,491,492,494,498,500,501,505,507,508,512,513
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] EXCEPTION **
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] on file '/var/www/projeqtor/model/persistence/Sql.php' at line (179)
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] cause = There is already an active transaction
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] => #0 /var/www/projeqtor/model/persistence/Sql.php (179) -> beginTransaction()
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] => #1 /var/www/projeqtor/model/PlannedWork.php (1186) -> beginTransaction()
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] => #2 /var/www/projeqtor/tool/cronExecutionStandard.php (46) -> plan()
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] => #3 /var/www/projeqtor/model/Cron.php (427) -> cronPlanningDifferential()
2018-09-11 10:38:46.698 ** ERROR ** [V7.2.2] => #4 /var/www/projeqtor/tool/cronRun.php (31) -> run()
2018-09-11 10:40:15.136 ===== TRACE ===== === SCREEN CUSTOMIZATION ISSUE =====================================
2018-09-11 10:40:15.136 ===== TRACE ===== Certaines customisations d'écran ne sont pas cohérentes :
2018-09-11 10:40:15.137 ===== TRACE ===== - Projet
2018-09-11 10:40:15.142 ===== TRACE ===== Les customisations ont été corrigées automatiquement
2018-09-11 10:40:39.610 ===== TRACE ===== === SCREEN CUSTOMIZATION ISSUE =====================================
2018-09-11 10:40:39.610 ===== TRACE ===== Certaines customisations d'écran ne sont pas cohérentes :
2018-09-11 10:40:39.610 ===== TRACE ===== - Projet
2018-09-11 10:40:39.612 ===== TRACE ===== Les customisations ont été corrigées automatiquement
2018-09-11 10:40:43.054 ===== TRACE ===== === SCREEN CUSTOMIZATION ISSUE =====================================
2018-09-11 10:40:43.054 ===== TRACE ===== Certaines customisations d'écran ne sont pas cohérentes :
2018-09-11 10:40:43.054 ===== TRACE ===== - Projet
2018-09-11 10:40:43.056 ===== TRACE ===== Les customisations ont été corrigées automatiquement
2018-09-11 10:43:30.783 ===== TRACE ===== Cron started at 11/09/2018 10:43:30
2018-09-11 10:59:32.271 ** ERROR ** [V7.2.2] Exception-[42S22] SQLSTATE[42S22]: Column not found: 1054 Unknown column 'ticket.idOrganization' in 'where clause'
2018-09-11 10:59:32.271 ** ERROR ** [V7.2.2] For query : select ticket.id as id, T1.name as nameProject, T2.name as nameActivity, T3.name as nameTicketType, ticket.name as name, T4.fullName as nameContact, ticket.idContact as idContact, T5.fullName as nameResource, ticket.idResource as idResource, convert(concat(COALESCE(T6.sortOrder,''),'#split#',T6.name,'#split#',COALESCE(T6.color,'')) using utf8) as colorNameUrgency, convert(concat(COALESCE(T7.sortOrder,''),'#split#',T7.name,'#split#',COALESCE(T7.color,'')) using utf8) as colorNamePriority, convert(concat(COALESCE(T8.sortOrder,''),'#split#',T8.name,'#split#',COALESCE(T8.color,'')) using utf8) as colorNameStatus, ticket.actualDueDateTime as actualDueDateTime, ticket.handled as handled, ticket.done as done, ticket.idle as idle, workelement.plannedWork as plannedWork, workelement.realWork as realWork, workelement.leftWork as leftWork,ticket.idProject as idproject from ticket left join project as T1 on ticket.idProject = T1.id left join activity as T2 on ticket.idActivity = T2.id left join type as T3 on ticket.idTicketType = T3.id left join resource as T4 on ticket.idContact = T4.id left join resource as T5 on ticket.idResource = T5.id left join urgency as T6 on ticket.idUrgency = T6.id left join priority as T7 on ticket.idPriority = T7.id left join status as T8 on ticket.idStatus = T8.id left join workelement as workelement on (workelement.refId=ticket.id and workelement.refType='Ticket') where ticket.idle=0 and ticket.idProject in (0, 512) and ( (ticket.idProject not in (0) or ticket.idProject is null ) and (ticket.idProject not in (0) or ticket.idProject is null or (ticket.idResource='12') ) and (ticket.idProject not in (0) or ticket.idProject is null or (ticket.idUser='12') ) ) and (ticket.idOrganization IN (5)) order by ticket.id desc
2018-09-11 10:59:32.271 ** ERROR ** [V7.2.2] Strack trace :
2018-09-11 10:59:32.271 ** ERROR ***** [V7.2.2] #0 Sql->query called at [/var/www/projeqtor/tool/jsonQuery.php:565]
2018-09-11 11:05:26.413 ===== TRACE ===== DISCONNECTED USER 'APO'

yesterday log file:

2018-09-10 08:14:09.130 ===== TRACE ===== NEW CONNECTED USER 'chd'
2018-09-10 08:23:44.473 ===== TRACE ===== NEW CONNECTED USER 'JRI'
2018-09-10 08:27:10.882 ===== TRACE ===== Login error for user 'jop'
2018-09-10 08:27:28.829 ===== TRACE ===== Login error for user 'jop'
2018-09-10 08:27:33.382 ===== TRACE ===== Login error for user 'jop'
2018-09-10 08:27:37.847 ===== TRACE ===== NEW CONNECTED USER 'jop'
2018-09-10 09:26:20.761 ===== TRACE ===== NEW CONNECTED USER 'dep'
2018-09-10 09:56:17.968 ===== TRACE ===== NEW CONNECTED USER 'fca'
2018-09-10 09:58:36.592 ** ERROR ** [V7.2.2] Exception-[42S22] SQLSTATE[42S22]: Column not found: 1054 Unknown column 'work.rate' in 'field list'
2018-09-10 09:58:36.593 ** ERROR ** [V7.2.2] For query : select work.id as id, T1.fullName as nameResource, work.idResource as idResource, T2.name as nameProject, work.rate as rate, work.idle as idle,work.idProject as idproject from work left join resource as T1 on work.idResource = T1.id left join project as T2 on work.idProject = T2.id where 1=1 and idResource in (18, 35, 55, 40, 62, 12, 25, 13, 60, 69, 59, 5, 41, 23, 71, 8, 63, 42, 9, 49, 52, 39, 57, 65, 58, 28, 70, 6, 22, 67, 48, 51, 31, 24, 33, 53, 44, 66, 30, 61, 21, 68, 1, 2, 47) order by work.id desc
2018-09-10 09:58:36.593 ** ERROR ** [V7.2.2] Strack trace :
2018-09-10 09:58:36.593 ** ERROR ** [V7.2.2] #0 Sql->query called at [/var/www/projeqtor/tool/jsonQuery.php:565]
2018-09-10 10:17:35.820 ===== TRACE ===== NEW CONNECTED USER 'ASE'
2018-09-10 10:18:20.579 ===== TRACE ===== DISCONNECTED USER 'ASE'
2018-09-10 10:53:51.943 ===== TRACE ===== NEW CONNECTED USER 'sba'
2018-09-10 15:53:58.258 ===== TRACE ===== NEW CONNECTED USER 'par'
2018-09-10 16:03:18.329 ===== TRACE ===== NEW CONNECTED USER 'APO'
2018-09-10 16:03:26.037 ===== TRACE ===== DISCONNECTED USER 'par'
2018-09-10 16:36:38.718 ===== TRACE ===== NEW CONNECTED USER 'fch'
2018-09-10 17:26:48.631 ===== TRACE ===== NEW CONNECTED USER 'ASE'
2018-09-10 17:27:07.789 ===== TRACE ===== DISCONNECTED USER 'ASE'
2018-09-10 18:07:26.320 ===== TRACE ===== DISCONNECTED USER 'fch'
2018-09-10 18:14:40.453 ===== TRACE ===== Cron started at 10/09/2018 18:14:40
2018-09-10 18:14:40.568 ** ERROR ** [V7.2.2] ERROR **
2018-09-10 18:14:40.568 ** ERROR ** [V7.2.2] on file '/var/www/projeqtor/tool/generateImputationAlert.php' at line (104)
2018-09-10 18:14:40.568 ** ERROR ** [V7.2.2] cause = Missing argument 1 for generateImputationAlert(), called in /var/www/projeqtor/model/Cron.php on line 427 and defined
2018-09-10 18:14:46.747 ===== TRACE ===== Cron started at 10/09/2018 18:14:46
2018-09-10 18:14:54.368 ===== TRACE ===== BackupDatabase has been done by the Cron
2018-09-10 18:14:54.472 ===== TRACE ===== Cron::run() - Calcul Imputation Alert for Resource
2018-09-10 18:15:25.381 ===== TRACE ===== Cron::run() - generateImputationAlert for cronImputationAlertCronResource at 1536332400 MAIL NO NO NO
2018-09-10 18:15:25.481 ===== TRACE ===== Calcul automatique du planning : calcul complet - Projets : tous
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] EXCEPTION **
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] on file '/var/www/projeqtor/model/persistence/Sql.php' at line (179)
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] cause = There is already an active transaction
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] => #0 /var/www/projeqtor/model/persistence/Sql.php (179) -> beginTransaction()
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] => #1 /var/www/projeqtor/model/PlannedWork.php (1186) -> beginTransaction()
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] => #2 /var/www/projeqtor/tool/cronExecutionStandard.php (62) -> plan()
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] => #3 /var/www/projeqtor/model/Cron.php (427) -> cronPlanningComplete()
2018-09-10 18:15:27.536 ** ERROR ** [V7.2.2] => #4 /var/www/projeqtor/tool/cronRun.php (31) -> run()
2018-09-10 18:19:41.986 ===== TRACE ===== DISCONNECTED USER 'dep'
2018-09-10 18:20:46.590 ===== TRACE ===== DISCONNECTED USER 'jop'

Hi,

Try and delete line in table cronexecution where functionName = 'cronImputationAlert'
(you should have 4 remaining lines where functionName starts with 'cronImputationAlert')

This will be included in patch V7.2.3

I have the lastest version of Projeqtor, I had delete all of line in table cronexecution with "alert", and also the cron start for a few minutes and stop itself.

what's the mistake?

last log file:

2018-10-03 09:13:39.496 ===== TRACE ===== Cron started at 03/10/2018 09:13:39
2018-10-03 09:14:09.753 ===== TRACE ===== Cron normally stopped at 03/10/2018 09:14:09
2018-10-03 09:14:11.605 ===== TRACE ===== Cron started at 03/10/2018 09:14:11
2018-10-03 10:00:02.231 ===== TRACE ===== Calcul automatique du planning : calcul différentiel - Projets : 67,80,144,185,187,188,197,234,235,240,292,363,376,380,381,421,425,428,432,433,435,437,457,460,462,466,468,473,476,477,479,480,481,482,483,489,490,491,492,494,498,500,501,505,508,517,523,526,527,528,529,530
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] EXCEPTION **
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] on file '/var/www/projeqtor/model/persistence/Sql.php' at line (179)
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] cause = There is already an active transaction
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] => #0 /var/www/projeqtor/model/persistence/Sql.php (179) -> beginTransaction()
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] => #1 /var/www/projeqtor/model/PlannedWork.php (1186) -> beginTransaction()
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] => #2 /var/www/projeqtor/tool/cronExecutionStandard.php (46) -> plan()
2018-10-03 10:00:03.490 ** ERROR ** [V7.2.3] => #3 /var/www/projeqtor/model/Cron.php (427) -> cronPlanningDifferential()
2018-10-03 10:00:03.490 ** ERROR ***** [V7.2.3] => #4 /var/www/projeqtor/tool/cronRun.php (31) -> run()
2018-10-03 10:00:03.490 ===== TRACE ===== Cron error : Une exception est survenue le 2018-10-03 à 10:00:03

Issue confirmed.
Ticket #3601 recorded
Will be fixed on next patch.