ios email client not fully displaying a powerpoint slide
PPTX (created in Office 2010) and then emailed as an attachment. When viewing this presentation via iPhone or iPad ios (9.3.1) email client, slide does not display fully. Only the images show and no text or background detail. Viewing it via Powerpoint on the iPhone or iPad slide displays as expected. Any advice as to why ios email client is doing this would be greatly appreciated. Thanks.
iPhone 6, iOS 9.3.1