This issue is that the security policy on a target Windows Server 2019 has some restrictions, which do not allow a remote scheduled tasks initiated by a DS-Client server.

Please refer to this Root Cause Analysis for more information on this issue.

To resolve this:

  1. Use the taskbar search box to find "Allow an app or feature through Windows Firewall"
  2. Scroll down to find the "Remote Scheduled Task Management Service"
  3. Tick all three of the 'Domain', 'Private' and 'Public' items. The 'Domain' option will show only if your computer is a domain controller.