Cron stopped...

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