I have connected the ECU with and ethernet cable, yet I don't seem to be connected to the internet.

Verify that you have plugged in the ethernet port and not the RS485 port of the ECU. Also verify that you are plugged in directly the router and not through a switch or a EOP (Ethernet over Powerline) device. Lastly, you may want to try another ethernet cable, as cables do go bad from time-to-time. [for commercial systems you can utilize the static IP feature using the ECU APP, determined by the IT manager of the business]