Trouble with arduino ethernet webservers

The device is connected over the mobile data network, and the arduino is either plugged into my router or my schools ethernet plug ins and neither work. in the setup i had the shield set up a dhcp address instead of an ip address i created. i used dhcp because my router did not allow me to create my own address, and i even tried changing the ports. i am not sure if that has anything to do with it.

EthernetServer server(80);
Ethernet.begin(mac);