My brother HLL3210CW printer suddenly fell off the network after several years. While trying to re-connect it would randomly see or not see the correct network but would not connect to it and return a message that it failed to connect. I am using a Netgear Nighthawk MK63 Mesh router system. The Brother printer requires a 2.4 Megahertz network which was available through the router but what I found was that with the router 2.4 Mhz in the AUTO setting for channel selection the printer would not connect. When I set the Channel selection to static setting to Channel 11 the printer connects immediately. Apparently the printer is very picky about what 2.4 Channel it wants. I did not try other channels to see if it would connect but Channel 11 works fine. Hope this helps some of you out there.