Checking the error message
When trouble has occurred, first check whether there are any messages on the printer's control panel or driver screen. If you have the notification email set when the events occur, you can promptly learn the status.
Network connection report
Diagnose the network and the printer status, and then print the result.
You can find the diagnosed error from the printer side.
Checking the communication status
Check the communication status of server computer or client computer by using the command such as ping and ipconfig.
Connection test
For checking the connection between the printer to the mail server, perform the connection test from the printer. Also, check the connection from the client computer to the server to check the communication status.
Initializing the settings
If the settings and communication status show no problem, the problems may be solved by disabling or initializing the network settings of the printer, and then setting up again.