Ethernet doesnt have a valid IP configuration

I was on the internet and everything was fine, then a few minutes later, my internet said it only had a "limited connection". I have to be connected to an Ethernet cord because my dorm room doesn't have wireless. I tried unplugging it, and plugging it back in, restarting the computer, and running the troubleshooting diagnostics. I even got my friend to plug her computer into my cord, and her internet worked, so its not the cord. It just continuously says that my "Ethernet does not have a valid IP configuration"