I need help with youtube on iphone 3G. it says youtube cannot connect

today. i upgraded my jailbrake/unlock iphone 3G 2.2.1 into jailbroke/unlock 3.0 Everything was working perfectly until I opened the youtube application. my iphone is connected to wifi internet, but the youtube application says cannot connect. It was working fine before the upgrade. why did this happen? does anyone else out there experiencing this? How do I resolve it? Please I need some answers to this because I need youtube feature on it.