Problem with iCloud Photos

Recently, when I go to my iCloud account, my pictures show up physically, but instead of seeing the picture itself, it comes up as grey with the warning sign on it. I can't even download them to my computer. When I attempt to, at the corner of my screen it shows that it responded, but it displays a message that it's waiting and nothing ever happens. I tried to restart my devices, turn off iCloud photos and turn it back on, and nothing seems to work. Does anyone know how to fix this? I would greatly appreciate it.