Use an envelope that has been stored in a dry environment.
Note: Printing on envelopes with high moisture content can seal the flaps.
Send the print job.
Does the envelope seal when printing?
Go to step 2.
The problem is solved.
Make sure that paper type is set to Envelope.
From the control panel, navigate to:
> Paper > > Tray Configuration > > Paper Size/Type >
Contact customer support.
Does your document print longer than expected? Checking the paper settings, reducing the number of pages, or removing held jobs are possible solutions.
How to Print on Chrome OS Devices