My Pixma Pro 9000 won't print on an A1 envelope 3 3/8 x 5 1/8

[mkujawa]

Has anyone had trouble printing on a smaller size sheet. Mine will not print on an  A1 envelope 3 3/8 x 5 1/8. I plan on calling customer service to see if I can get anywhere, but figured I would try here too. I am running Mac OS X Version 10.8.5 and using Illustrator 6.

Thanks a million,

Margaret