Canon PIXMA MP600R Setup Manual page 26

If Client-to-Client Blocking is enabled
Disable the Client-to-Client Blocking function while using the machine.
Some access points are capable of switching automatically between wireless channels. This machine
may not be able to connect an access point if its channel is set to automatic or the equivalent, or to a
channel outside of the range 1 to 13. Configure the access point to use any channel between 1 and 13.
Confirming the Setup Environment 23