i can not use my youtube app...mor can i view any videos y?

[new2iphonepleeeeasehelp]

when i try to go to youtube it instantly says that it cannot connect to youtube and if i ever click to view any video from youtube on any site it says the same thing. and if there is another site that has a video that u can watch on my iphone it has like a grey and white like "dont" sign on the video and im assuming this means that i do not have the capabilities to view video... what can i do? download a video app? if so which one? and what do i do about youtube?