Hi
Based on the error message, this appears to be a physical layer issue.
Please try the following to see if it helps:
- Replace the Ethernet cable with a different one, including the one included with Flint 2 and others known to work properly
- Try configuring Flint 2's LAN 1 port as WAN and connect to the ISP modem using this port
Port Management - GL.iNet Router Docs 4 - Try adding a dumb switch between Flint 2 and the ISP modem