When i use CDN, cache not work properly

Hello,
webpagetest is a really helpfull guide to optimise my work and give better sites to the users! That why i love it! But today i have a problem thats why i seek your valuable help!

i have optimized my site and i get the 5 A!! (great!!)
http://www.webpagetest.org/result/141110_F2_14Z6/

But soon my site will be translated in more English too, because i will go further for customers out of my boarders, thats why i installed a CDN to my site!

But when i use the CDN the “Cache static content” drops to D insteed of A.
http://www.webpagetest.org/result/141110_46_16EX/

Any clue why is this happening??

Looks like the expores time on the CDN resources is set for 7 days (which may be good enough depending on what your needs are). WebPagetest tends to prefer 30+ day expires. If you get a lot of people visiting for extended periods of time then longer expires are probably worthwhile (and it’s probably a setting somewhere in your CDN’s control panel).