iCloud backup causes Airport Extreme to crash

Hello All,

I've spent about two hours trying to figure this out via resetting my router settings and looking online. My problem is this - whenever I plug my iPhone 6 or my fiance's iPhone 6 Plus into the charger and let the screen lock/go black, my internet stops working for all of my other devices/computer. I have narrowed it down to iCloud backup by turning that feature off and plugging the phones back in, which does not result in the same router problems. I cannot figure out why a simple backup process slows my entire internet down to a complete stop. I have already tried changing the DNS to google's 8.8.8.8 and 8.8.4.4 with no resolution to my problem. Is there anyway to prevent this from happening without having to just plug my phone in at night only when I'm going to sleep?

Thanks