[SOLVED] error on creating simulation base

when i try to create a simulation base cron stopped and it is writing on log file :
2023-06-22 11:30:15.772 ===== TRACE ===== Début de suppression d'un environnement de simulation - base test
2023-06-22 11:30:15.772 ***** ERROR ***** [V10.4.1] EXCEPTION *****
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] on file '/var/www/html/projeqtor/model/DataCloning.php' at line (1003)
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] cause = Call to a member function exec() on null
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => #0 /var/www/html/projeqtor/tool/cronExecutionStandard.php (157) -> deleteDataCloning()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => #1 /var/www/html/projeqtor/model/Cron.php (547) -> dataCloningCheckRequest()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => #2 /var/www/html/projeqtor/tool/cronRun.php (39) -> run()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] Call to a member function exec() on null
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] Exception while executing CRON script : fix the source issue and manually restart the CRON Process
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] === Trace Stack for last error ===
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => /var/www/html/projeqtor/tool/projeqtor.php at line 1553 calling debugPrintTraceStack()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => calling exceptionHandler()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] ===
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] CRON abnormally stopped
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] === Trace Stack for last error ===
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => /var/www/html/projeqtor/model/Cron.php at line 308 calling debugPrintTraceStack()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => /var/www/html/projeqtor/tool/cronRun.php at line 35 calling Cron:abort()
2023-06-22 11:30:15.773 ***** ERROR ***** [V10.4.1] => calling cronAbort()

how can I purge it ?