How to check/change Daily Maintenance Task execution time?

The behavior is configured by /etc/crontab file:

# cat /etc/crontab
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# m h dom mon dow user command
14 * * * * root cd / && run-parts --report /etc/cron.hourly
9 2 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
15 1 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
33 1 10 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
#

In this case, cron.daily is executed on 02:09 AM every day.

Daily Task script is run by /etc/cron.daily/50plesk-daily script. To change the time of execution cron.daily jobs, edit /etc/cron.d/dailyjobs :

CONFIG_TEXT: # Run the daily, weekly, and monthly jobs if cronie-anacron is not installed
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root

# run-parts
23 3 * * * root [ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.daily
21 4 * * 0 root [ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.weekly
58 4 29 * * root [ ! -f /etc/cron.hourly/0anacron ] && run-parts /etc/cron.monthly

In this case, cron.daily task is configured to be run on 3:23 AM.

Note: Cron uses 24 hour time format.

Execution time is configured in /etc/anacrontab by the parameter START_HOURS_RANGE :

# cat /etc/anacrontab
# /etc/anacrontab: configuration file for anacron
# See anacron(8) and anacrontab(5) for details.

SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
# the maximal random delay added to the base delay of the jobs
RANDOM_DELAY=45
# the jobs will be started during the following hours only
START_HOURS_RANGE=3-22
#period in days delay in minutes job-identifier command
1 5 cron.daily nice run-parts /etc/cron.daily
7 25 cron.weekly nice run-parts /etc/cron.weekly
@monthly 45 cron.monthly nice run-parts /etc/cron.monthly

Note: the "delay in minutes" column. It means that with a parameter START_HOURS_RANGE= 3 -22 cron.daily scripts will be run on 03:05 AM. As this behavior may appear a bit sophisticated, you may refer to an official documentation of Oracle Linux for details.

Open Control Panel > Administrative Tools > Task Scheduler . In Task Scheduler Library find a task with a name Plesk Scheduler Task #{UUID} and a description Daily script task . Open its properties, change to tab Triggers and edit the trigger with desired values of start time.