Canon LBP7780CX User Manual page 917

The printer and the authentication server use different IEEE802.1X authentication systems.
Change IEEE802.1X authentication systems.
Solution
"Setting IEEE802.1X Authentication"
IE No reply from the destination.
<Cause> During IEEE802.1X authentication, and error occurred while communicating with the
authentication server.
Solution Check to see if the cable is disconnected.
IE Set necessary authentication info.
<Cause> There is information missing from the IEEE802.1X authentication settings.
Check the IEEE802.1X settings, and reconfigure them.
Solution
"Setting IEEE802.1X Authentication"
IE Set the correct authentication info.
<Cause> An error was returned from the authentication server because the certificate used for
IEEE802.1X authentication is not correct.
The certificate used for TLS authentication is not correct. Check the certificate, and reconfigure it.
Solution 1
"Setting IEEE802.1X Authentication"
Solution 2 If the printer's certificate is correct, check the authentication server's CA certificate.
IE The certificate has expired.
<Cause> During IEEE802.1X authentication, the certificate received from the authentication server
was an expired certificate.
Solution 1 Check the authentication server's certificate.
Check the printer's and the authentication server's time settings.
Solution 2
"Turning the Power On and Specifying a Language"
IE The certificate is incorrect.
<Cause> During IEEE802.1X authentication, an error occurred as a result of the verification by the CA
certificate of the certificate received from the authentication server .
Solution 1 Check the authentication server's certificate.
Install the CA certificate in the printer.
Solution 2
"Security Settings"
NW Competing IP add. found on the network.
<Cause> The IPv4 address set for the printer overlaps with another host on the network.
Change the printer's IPv4 address and restart.
Solution