Specially after the system copy operation, your DB13 job might fails with the “exception CX_DB6_CALENDAR_ACTION in class CL_DB6_CALENDAR_ACTION method” meantime you can see the below error message in transaction SM21

BP_JOB_MODIFY: Cannot modify job .
Reason: Job DBA<jobname>…..contains invalid data
BP_JOB_MODIFY: Cannot modify job DBA*No background processing active on TargetServr <server id>

DB13 Output ;

SM21 Output ;

SOLUTION ;

In this case, Please open the transaction DB13 and open the below area ;

DBAcockpit -> Jobs-> Back-End configuration

To solve the issue, assign the “Background Server” information in the related area ;