Nightly cleanup not starting in given time window

Somtimes it happens, that the nightly cleanup does not start automatically in the given time window.
Is there any chance to figure out why this happens?

My environment:
urback server 2.4.13 running on Windows10 Build 18363.
Backing up 17 Clients (Windows10 and ubuntu).
Time window for Cleanup is: 1-7/15-18
I am doing daily incrementals (max 124), no fulls. Image backups (max 4) every 45 days.
Please let me know if I should provide any addtional details.

I have already tried to analyze app.log and urbackup.log* in C:\Program Files\UrBackupServer.
But I could not find any hints.

Thank you for looking into this.

P.S.: I am using urbackup since 3 or 4 years now. A really great pice of sotware making my life easier.

Is it possible the Windows10 machine is going to sleep before the nightly cleanup? This consumer OS defaults to power savings which reduce performance and force sleep when idle too long. I change the power settings to maximum performance, no sleep as quickly as possible on the sets I administer, for UrBackup and for the users.

Hi Don,
All powersaving settings are disabled on this machine, so I dont think that this can cause the issue.