I have a Canon MG6450 which may be a bit different. In the information screen has 3 pages - normally set on Copy/ Scan/Cloud. On page 2 is the WLAN that can be on (blue light showing on left of top dashboard). Is the blue light on? Maybe it was inadvertently switched off ?
I have a Netgear router which shows (In "Netgear Genie") what devices are on the net - maybe your router has such a menu?