Can't add image to product in List New Product Field

I'm having a problem adding extra pictures a product listing. I can upload a picture in the featured image section perfectly, however when I attempt to add other pictures into the actual post I get a blank screen.
I get to the first screen that asks me to add a picture from my computer or my media gallery, I'll select my option, then I'm sent to this blank screen and the picture won't be added to the post. I've uninstalled & re-installed my plugins and even the theme I'm using. I'm using multisite, and this issue only occurs on the main site thankfully.