Canon MB2100 SERIES Online Manual page 1232

3415
Cause
Communication with mail server failed.
What to Do
Press the printer's OK button.
Make sure that the address and port number of the incoming mail server (POP3 server) in mail server
settings are correct with Remote UI.
Setting Mail Server
If the error is not resolved, check your mail server condition.
For settings and condition of your mail server, contact the administrator of mail server.
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