Confirm that the peer device supports 1Gbps port and negotiates 1Gbps with other router.
Please try to replace other network cables.
Re-plug the network cable several times.
Other devices are connected to MT3000 WAN. Regardless of whether it is an ISP modem, router, or client device, as long as it supports 1Gbps, you can see the current negotiation rate in the GL GUI after connecting. We only look at the negotiation rate to ensure that there is no hardware problem with this port.