Hello tchen1019,
Your MF8280Cw supports printing on Com 10, Monarch, C5, and DL size envelopes. So that I have a better picture of your situation, could you answer a few questions?
(1) What size envelope are you trying to print?
(2) Are you loading the envelope in the Manual Feed Slot or the Paper Drawer?
(3) Is there an error message appearing on you computer or printer when attempting to print the envelope? If so, please list the message verbatim.
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