When "Render print jobs on client computer" is disabled, users are not able to select a specific print tray when printing from Microsoft Word to a Canon printer.
When you have the box "Different First Page" selected on a word document, it will prevent you from selecting the printer tray of your choice when "Render print jobs on client computers" is disabled.
Disable "Different First Page" from within Word.
1. Got to View -> Header & Footer
2. Uncheck "Different First Page"