Since its unclear what the scheduled task is for and expecting the server to be behaving based on load distribution during the day.
First task runs at 6 a.m (Last for 3 days)
Second time it runs at 2 PM (Last for 3 days)
Third time it runs at 10PM (Last for 3 days if running)
Assuming the load to be based on day time when users are most active, would like to ask you to check the performance of the system during the said interval that second task is assigned for and validate the logs for the task ID initiation date/time and stopped date/time to avoid multiple instance or resource locking issue.
Please also try manually running the task during the day time and check the status of the task before starting it manually.
We expect the load or multiple instances be the reason for the task to be causing the failure.