3100cn printer will not accept #10 Envelopes in MPF tray

When trying to print a #10 Envelope from Word, I get a message on the printer panel to "Load Envolope #10" when in fact they are already loaded.

 

On the printer MENU, the MPF is set to "Free Size" paper size.  I tried printing by changing that to Envelope #10 but it still did not recognize that there were envelopes in the MPF tray.

 

Are there any tricks to make this work?  I am inserting the envelope short side in first since it is a #10 envelope and cannot be inserted long side first.

 

Any help will be appreciated.