Canon imagePROGRAF GP-4000 - Manual (Page 926)

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Cause
Communication with mail server failed.
What to Do
Tap OK on the touch screen to dismiss the error.
Check that the mail server and device secure connection (SSL) settings match.
Check the secure connection (SSL) settings in Remote UI .
Setting Mail Server
Contact the mail server administrator to configure a secure connection (SSL) to the mail server.
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