Why does service authorization fail in Windows 2003?

Question

Windows

Is Windows Server 2003 St in the domain. It has a server application for working with commercial equipment. Some parts of this application run as services, some as COM+ applications. All these services run from a local account (not a system account), and COM + applications run from the built-in U.Z. domain administrator (that's how they installed it) and under other U.Z. they refuse to work.
Periodically, about once a day, this server application stops working, and in order for it to restore its work, you have to re-enter the password from U.Z. under which COM + applications about which I wrote above work. Also, after a reboot, one of the services mentioned above does not start. You also have to drive in the password again from U.Z. under which it spins.
Can you please tell me what can be the cause of the problem?

Answer 1

Tried to put the launch of these COM + applications as NT services, then the application stops working.
I understand that there should be a connection between the authorization of COM + applications and services, but I don’t know where to look for it.