My Desktop PC Won't Connect To The Internet Via Ethernet Cable In My Dorm Room

The device I am trying to connect is a custom-built desktop computer. I am attempting to connect via ethernet. I have the ethernet cable plugged into the ethernet port on my computer and the ethernet port on the wall. Windows Network diagnostics says that my broadband modem is experiencing connectivity issues. I tried using a different ethernet cable but that did not change anything. If yall have any ideas please let me know.