This is the download page for your RM. You find the firmware files in your PreSonus accout. There is latency/lag known for FireWire connections (see release notes), but not or WiFi. Could it be that there was a conflict of network IP addresses? Or problems with electricity? Was the router powered off somehow? If it worked again after restarting the RM mixer, it looks like the router was able to handle IP addresses again, so that the network could be established again.