The agent can be installed on these OS's. You will need to support 2003 servers agentlessly with direct scans.
Windows Vista Family
Windows 7 Family
Windows 8 Family, excluding Windows RT
Windows 10 Family
Windows Server 2008 Family
Windows Server 2008 Family R2
Windows Server 2012 Family
Windows Server 2012 Family R2
Windows Server 2016 Family
I am having trouble in Agentless scanning as of now. That's why some of my endpoints I installed an agent.
Is there any chance that you could provide me a older version of agent. Like version 9.0
Sorry, we can only provide support and access to 9.2 and 9.3 and neither support installing the agent on 2003 servers. Also, older agents can't check-in with newer console.
Can we help you overcome your agentless scan issue or is it a known environmental issue?
The agents are not compatible with Server 2003, there is nothing we can do to install an agent on them. We don't have a guide to troubleshoot NTLM authentication, I would assume there are some on the internet somewhere. The case is escalated to our back-line support team so you are in good hands.
Unfortunately there isn't much we can do if a GPO or firewall is causing issues after changes, but here are my 2 cents:
You should verify this isn't set: Network Security: Restrict NTLM: Incoming NTLM TrafficDeny All Accounts
Verify SMBv1 or SMBv2 are not disabled.
This has fixed similar issues in the past: Microsoft Security Bulletin MS16-101 - Important | Microsoft Docs
If possible, you should verify the issue by reverting one of these 2003 servers, just to be sure the changes are the root cause.