A non-Acronis application blocks Port 69

Try reinstalling OS Deploy Server and switching from multicast to unicast to solve the issue

Test of the command fails because the user is impersonated differently in Remote Desktop Session. The actual command within the backup plan will be executed fine

Acronis Snap Deploy 4 is not compatible with Acronis Backup & Recovery 10 PXE Server

Add user to the "Bypass traverse checking" and "Act as part of the operating system" security policies