Won't coect to ethernet

Hi, I'm ruing Ubuntu Server on the Raspberry Pi using the ARM version of the OS. I'm ruing the Raspberry Pi in headless as I don't have a monitor to plug it into. I ran into a problem a few hours ago when I was setting up a LEMP stack. I installed Nginx, PHP, and MariaDB using headless by coecting my Raspberry Pi to my router using etheet and sshing into it from my laptop. After messing with the configs I restarted the Raspberry Pi from ssh instead of reloading nginx because it's easier to do. When the Raspberry Pi rebooted, it would not coect to the network, so I tried restarting it many times and using two different etheet cables and 3 different etheet jacks on my router. Anyone know what could be wrong or how to fix it?