Host seems down Error for Legacy

Hello,
I have started the Legacy machine and used, nmap -A -T4 -p- 10.10.10.4 , but it returns host seems down.
Confirmed that I am connected to the VPN, regenerated the key and switched the server.
Used nmap -A -Pn 10.10.10.4 command, which told me host is up.
I tried the same on 2-3 different machines but received the same error.
Also I am a VIP user.
Please help!!
Thanks

A little late maybe for a response, but if you’re still having this issue its because you didn’t use the -Pn flag on your first scan.

By default, nmap will ping machines to check they are up before performing a port scan - if the machine does not respond to the ping (because it is down, or because of a firewall configuration, etc.), nmap does not perform the port scan. You can add the -Pn flag to say “nmap, i know this machine is up, do the port scan even if it doesn’t respond to your ping”.

You can read up more info here : Host Discovery Controls | Nmap Network Scanning