Screen sharing not working on OS X 10.11 El Capitan
Sounds like one computer isn't able to reach the other.

Try using vnc://myhomemini.local

Adding the .local tells your Mac that it should use bonjour (multicast DNS) to resolve the address.  If everything is on the same network and multicast is allowed (usually the case) this should allow your computers to find each other.  

Another possibility is that your network is configured not to allow hosts to talk to each other.  So even though they are on the same network, the router doesn't allow them to talk.  Look at the settings on your router to determine if that is the case or not.