You may have noticed that in your Site Servers, the "Symantec Network Boot Service (TFTP)" service shows as "Stopped" under the "NBS Server" tab.
When you tried to start "Altiris PXE MTFTP Server" service manually under "Services",
you got the following error:
Services
Windows could not start the Symantec Network Boot Service (TFTP) service on Local Computer.
Error 1053: The service did not respond to the start or control request in a timely fashion.
Release : 8.7.1
Microsoft Visual C ++ is missing
Install missing Microsoft Visual C ++ fixed the issue.
In this example, Microsoft Visual C++ 2015-2022 Redistributable (x64) - 14.30.30708
"PXE-E99 May be seen while PXE booting in certain sites after upgrading Deployment Solution to 8.7.1" (KB 275767)