Canon MG3600 series Online Manual page 732

Locate your smartphone/tablet close enough to communicate with the machine.
Check for obstructions.
Check7
Wireless communication between different rooms or floors is generally poor. Move the machine as necessary.
Make sure there is no source of radio wave interference nearby.
Check8
If a device like a microwave oven that emits radio waves of the same frequency bandwidth as a wireless router
is nearby, it may cause interference. Place the machine as far away from the interference source as possible.
Make sure 5 devices are already connected.
Check9
Access point mode does not allow more than 5 devices to be connected.
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