It is recommended to refresh and try again. Look at the lower right corner of the computer first to see if there is a red cross in the small computer. If so, the network cable is not plugged in properly. See which side of the network cable is not plugged in properly before plugging it in. If there is still a red cross, it may be that the network cable connector is not good. Make a new crystal head or change the network cable. If the laptop is wireless, there will be an asterisk in the displayed signal, indicating that there is no signal. Maybe the routing power is not plugged in properly or the router is broken. If there is no problem with the network cable connecting the computer, it depends on whether the switch or router is connected online to ensure the smooth line. If there is nothing wrong with the external hardware of the computer, see if there is an exclamation mark in the lower right corner of the computer, which shows "Limited or No Connection", indicating that the IP address configuration of the computer conflicts with others. Change another IP address, or choose to automatically select an address.