Select the device certificate to be used for S/MIME using Web Image Monitor.
Log in as the network administrator from Web Image Monitor.
Point to [Device Management], and then click [Configuration].
Click [Device Certificate] under "Security".
Select the certificate to be used for the electronic signature from the drop-down box in "S/MIME" under "Certification".
Click [OK].
The certificate to be used for the S/MIME electronic signature is set.
“Updating...” appears. Wait for about one or two minutes, and then click [OK].
If the previous screen does not appear again after you click [OK], wait for a while, and then click the web browser's refresh button.
Log out.
If the selected device certificate expires, signatures cannot be attached to e-mail. Select a certificate that is within its valid period.