Canon imagePROGRAF PRO-300 13" Photographic Inkjet Printer - Manual (Page 533)

Check3 If using WPA/WPA2 key or a password, make sure encryption key for
computer, network device, and printer matches key set for wireless router.
The length or format of the Wi-Fi password and authentication method must be identical among the wireless
router, the printer, and your computer.
For details, see Setting an Encryption Key .
With Encryption On, Cannot Communicate with Printer After
Changing Encryption Type at Wireless Router
If you change the encryption type for the printer and it subsequently cannot communicate with the
computer, make sure the encryption type for the computer and the wireless router matches the type set
for the printer.
Cannot Communicate with Printer After Enabling MAC/IP Address Filtering or Encryption Key on
Wireless Router
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