Hardware failure: check whether the display light, power supply and connection of the switch are normal, and whether the switch is normal.
Setting failure: 1. Check whether the switch has an Internet Protocol Address set. If an Internet Protocol Address is set that is not in the same network segment as other devices, delete it or set an Internet Protocol Address that is in the same network segment as other devices. 2. Failure of VLAN setting. Several ports connected to the switch belong to different VLANs, so they are blocked. Remove or modify the set VLAN to the same VLAN.