It means what it says.
Two devices with the same IP address, on the same network, cannot connect at the same time - each device must have a different address.
On a small home network, that's usually very easy to fix. If you have manually set the IP address, just change the last set of your IP to a different number. In your example, change your own IP address to 192.111.1.12
If you have your router set to supply DHCP addresses, this usually is not necessary, as the router won't give out the same address to two devices at the same time. Then you would make sure that each device is set up to accept the output of the DHCP server. That would fix it, too.