Switch caused problems to the network

It took me really long time to understand why It was happening that but I finally found it!

I thought I had TL-SG105 but in reality I had TL-SG105E which is "smart" switch and by default t was getting the IP 192.168.0.1, which was the same as my router! That's why all this mess..

Once I changed the switch's IP with a different one, all fixed.

After my experience this is caused by a loopback in the network.
This is not necessarily because of the switch, but can be caused by a bad cable or a bad device plugged into the switch.

This is an unmanaged switch that means you can not configure it. It will learn the ip/mac addresses on the network by itself.

The loops in the network are most often caused by hubs (you just want to get rid of those). What a hub does, it sends all of the data it receives on one port to all other ports. If you connect two ports on a hub together, there will be an infinite loop and I saw this bring down even huge networks.

You should troubleshoot the devices. It might be caused by the switch, it might be caused by a bad cable, and might be caused by any devices connected to the switch.

There must be a network congestion or cable looping issue on your work. To find this, remove all network cables from the switch, and put one by one. Then find on each computer, is there any weird behavior, slowness etc.

Also check with a spare switch, the same issue happens in a network, there must be problem in system's side NIC also.

This is L2 level switch, no configuration required for each port, and will work as plug and play.