not uploading images

Hi there

I have installed NextGen Gallery, the add-on media library, and the add-on optimizer. It lets me select images from my media library, but when I click “add to gallery” it stays in the uploading process indefinitely. I’ve been trying it with even just one image, and it still doesn’t move forward. The images have been optimized at a max width or height of 600px. Please help.

Thanks

https://www.ads-software.com/extend/plugins/nextgen-gallery/