HTML5 banners really laggy / slow to load

Hey there gang, my published html5 banners are being rejected by the media company and it seems they take an age to load. I am not sure why, it's the same way I have been creating banners for a while and haven't had this issue before. It seem to validate fine but is slow to load.

here is a link to my rejected banner

https://www.dropbox.com/sh/nr21obf2hdzwcif/AADpEAV1u3vZ10H_Zt8ExSRWa?dl=0