I’m getting an IP conflict error with my network,

Greetings!
I’m getting an IP conflict error with my network, and I hope someone can explain to me why I have this problem and how to fix it. I have set up my network by having two virtual machines with separate network card for each of them.
Every time I turn them on, I get an IP conflict problem with one of the machines. I’m also using a 10.X series to connect these machines to the network and I designated a 192.x series address to the two machines.
How do I resolve this issue?
