Can't Start Systemd Timer

I have the following systemd timer configuration

[Unit]
Description=Timer for Service

[Timer]
Unit=service-unit.service
OnCalendar=Mon..Fri *-*-* 13..23:0,15,30,45:00
# *-*-* means every day and 10:00:00 is the time of day (UTC)

[Install]
WantedBy=timers.target

When attempting to start the timer I receive the following error message:

Failed to parse calendar specification, ignoring: Mon..Fri *-*-* 13..23...5,30,45:00 service-timer.timer lacks value setting. Refusing.

I tried checking the timestamp with systemd-analyze calendar "Mon..Fri *-*-* 13..23:5,30,45:00" but my version does not seem to have this option. It returns Unknown operation 'calendar'.

When attempting on a different server where the calendar option is available it seems to be a valid timestamp.

$ sudo systemd-analyze calendar "Mon..Fri *-*-* 13..23:0,15,30,45:00"

  Original form: Mon..Fri *-*-* 13..23:0,15,30,45:00
Normalized form: Mon..Fri *-*-* 13..23:00,15,30,45:00
    Next elapse: Thu 2020-09-10 14:00:00 EDT
       (in UTC): Thu 2020-09-10 18:00:00 UTC
       From now: 1min 21s left

The server where it is not working is CentOS 7 and the server where it is working is Ubuntu 18.04 Minimal.