internet not working when connected via ethernet?

[AmateurLover650]

Hi, I am trying to connect my apple tv 3 to my universities internet network, the wifi uses wpa2 enterprise and thus didn't work, I have now unplugged the ethernet from the wireless access point and plugged it into the applet tv, but their is still no connection to the internet, even when i plug my mac into the ethernet there is no internet, why? the wireless works fine when its plugged in, so it can't be a faulty outlet. do i need to enter my university login details somewhere to complete the connection?