Would you suggest not connecting to the vps then or can I ignore the warning?
You should never ignore this type of error! Instead, try to find the cause of the problem and find a suitable solution, because this could be an attempt to snoop on your communications. Try these steps out, read the accompanying link and see if this helps you sort it out.
1) Are you trying to connect to the VPS by IP address?
It is common for this error to be thrown up if you are trying to connect using the IP address instead of by name, because the IP address isn't actually on the certificate. Try connecting by name and see if this does not correct the issue.
2) This type of error could be the sign of someone trying to snoop on your connection.
This error is common when someone is trying to get you to accept a malicious certificate so they can sniff your encrypted connection. If this is a malicious certificate and you accept it, then the attacker will be able to intercept all contents of this connection in plain-text. This would include, but not be limited to: key exchanges, passwords, take control of the current session, etc.
3) What would be the impact of accepting a malicious certificate?
Well, it largely depends on how often you reuse passwords, if you're exchanging files back and forth to the server, etc. Since all of your VPS communications would then be compromised, it would be trivial for an attacker to place malicious files on the VPS for you to download, serve you with malicious files during transmission, use the VPS to attack your home network - since you most likely allow it through your firewall, etc.
For additional help, check out:
Edited by Kaosu, 27 June 2014 - 09:57 PM.