Need help with making sure i am on the correct HTB server

Hello anyone who can help, I am new to HTB been here about a week. Need advice on why my nmap scans are sometimes coming back showing information but other times not. Just started trying Active machines, and no matter how many different types/scripts scans i run the results are different. I know this is a very broad question, just need some advice. I was wondering if it had anything to do with which server I am connected to on the HTB site? First machine i followed a walk-through and everything went according to the results of the right-up. After moving to Active machines my scanning results have fluctuated. I am new to this and still learning just feel like I have tried everything and cant find a solid answer. If anyone can point me into a certain direction that would be greatly appreciated. Might add that i am new to hacking/exploiting just started this year, so its possible i am just missing the mark? Thanks for any responses