It may be a hardware failure or a setting failure. If there is a hardware failure, you should check whether the display light, power supply and connection of the switch are correct and whether the switch is normal. If the setting failure, first check whether the switch has set an IP address. If it has set an IP address that is not in the same network segment as other devices, delete it.
Or set an IP address that is in the same network segment as other devices; then see if it is a fault with the VLAN setting. If the switch is set to a different VLAN, the ports connected to the switch belong to different VLANs, so it is blocked. At this time, you only need to remove the set VLAN.