YouTube videos won't play on iPhone?

YouTube videos won't play. It just keeps loading. And also my safari and mail won't work as well. Whenever I go into safari it just flashes out. And when I go to mail it's just frozen and it flashes out after a while. If anyone knows how to fix this please tell me how? That would be a great help. Thank you:)

You might have run out of internet data, this happened to me once, some networks shut down hard to launch programs such as YouTube so you won't go above you limit (assuming you're on contract) ask if you can go above your limit or wait another month!

Because Apple refuses to allow Flash technology on their devices. The way around it is to use the YouTube app. That will play all YouTube vids.