Airport is telling me that the ethernet cable is unplugged, but it is not

My Airport is telling me that the ethernet cable is unplugged. I have unplugged & replugged the cable, I then tried restarting the Airport, my computer & my router, I also did a soft reset & then a factory reset, no change. I plugged the ethernet cable directly into my computer and the internet and cable worked fine, just not when it is connected to the Airport. Nothing was changed with the Airport or router, it wasn't moved or dropped. Is there something wrong with the ethernet port? Can this be fixed? Thank you in advance for any help you can give me!