Canon LBP7100Cn User Manual page 263

Clicking [Check NTP Server Connection] initiates communication with the NTP server specified in [NTP Server Name],
and the communication result is shown in [NTP Server Connection Check Result] as follows.
[OK]
[Error]
Proceed to Step 3
3
Restart the printer.
Turn the printer OFF, make sure that the Main Power indicator is off, wait for 10 seconds or longer, and then turn it ON
again.
After the printer is restarted, the settings become effective.
Able to successfully communicate with the NTP server
Unable to communicate with the NTP server due to incorrect setting or communication
error
if you do not specify the settings for the other options.