RH199 - Practice: Editing Network Configuration Files problem

I reset both ServerX and DesktopX . The instructions indicate to add two entries to /etc/sysconfi/network-scripts/ifcfg-eth0: In my case IPADDR1=10.0.1.1 for Server1 and IPADDR1=10.0.1.2 for Desktop1, and PREFIX=24 for both. When I do this on either system if fails after executing "nmcli con reload" and then "nmcli con up". See attached screenshot.
Any ideas?

Thanks,
Mark