main Deco——Switch ---port 2\3\4 connecting to wired devices.

other wireless devices are connecting wirelessly? all of them are connecting to Deco network.

You can't ping wired devices from wireless devices?

The first tp link has connected some devices that all work and have v3 Model number: TL-SG108. From this it is also connected swich nr.2 which also has V3 model TL-SG105 that stops the internet. Swich nr3 is the VI3 model D-Link DES-100BD and connected to swich 2. Swich nr4 is the same model and version as nr.2 and connected to swich 3. No one has IP address required.

I have also purchased a TP-link TL-SG108E V3 that has iPad 192.168.0.1 which is the same as network.

Is it the old D-Link that is the problem?

yes, I have the same issue as yours before.

After I changed the D-Link switch or remove it, the network gets back normal.

I consulted tp-link support by email before, they replied me as below:

Dear Customer,
[FONT=arial]Recently we get some feedback that Deco cannot work properly while connected to some [COLOR=red]D-Link switches. [/FONT]
[FONT=arial]After a series of tests, we find that it's because some [COLOR=red]D-Link switches cannot handle and forward the Ethernet II control message that based on the standard IEEE 1905.1 protocol, which is used to set up a wired network. TP-Link and other brands of switches can forward these packets normally.[/FONT]
[FONT=arial]Regarding this case, it's recommended to replace the [COLOR=red]D-Link switch with another one for a check. Or contact D-Linksupport for a solution.[/FONT]