There are too many variables with all the missing info you left out.
It cannot be page size because that would fault the machine immediately.
It can be the banner page that is printing if it is a 1 envelope being printed 250 times scenario.
So try this:
Or in the FX driver (Make sure separators isn't enabled too)
It can be that the doc printed is 2 pages and only one has content.
In Word that could be fixed ala:
Hi All,
I was wondering if there is a setting on the printer that might be causing this issue. Or is the paper size selection causing it?
We are using the Bypass tray and printing to an envelope, the paper size DL Envelope (110x220mm)
The printer will print 2 copies for every print job. One will have the correct information printed perfectly and the second will be blank.
So I have 250 envelopes I want to print addresses to and the printer is saying I have a 500 prints to complete?
Thanks for you help.