Who is your ISP and how are you trying to connect? Wirelessly or wired? If wirelessly, try using a wired (ethernet) connection instead. Works much better typically.
Or is this some sort of settings issue? Have you tried changing the DNS at all?
Am a new 'smart tv' owner - the Samsung set is working fine except that we're unable to connect directly to the internet (our PC connectivity is a-ok). Coding on back of the tv set is: model #UN55J6200AFXZA, version US02, s/n 04K73CAH110914A. Please advise - thanks!