Hi, I have been having this problem where by my 1Gbps connection will sometimes show 1Gbps in link speed and sometimes show 100Mbps. So I tried to change the speed and duplex manually to 1 Gbps, and it worked for 2 days before internet was totally cut off. I had to change it back to auto negotiation for it to work again, and when I changed it back it showed a link speed of 100mbps. I tried the diagnostic and it said my cable link is only capable of 100Mbps. Last resort, I called my ISP but also to no avail. I unplugged and plugged the ethernet cable back and it showed now I am running 1 Gbps speed, the diagnostic this time said that the cable was running at its max speed. I am lost as to what went wrong, and this issue only affects my LAN line, my wifi works as intended.