Check that the RJ45 is seated correctly in the port on the router. I mention this, cause this is the "are you freaken kiddding me?" Scenario, that you could spend hours troubleshooting.
Next, plug a computer/laptop into that port. Verify it's working. Then? Test the cable run by the switch. Make sure you can get connection at the switch side.
If all that passes, all these tests, just assume your router hates your taste in switches.