@TP-Link 

Well, in my case I have three "brand new" never registered, or used Deco X68 and am having the same issue. Installed as instructed, updated firmware, rebooted, removed from the mesh, rejoined them, you name it.

I ended up opening a ticket with TP-LINK support directly. Extremely disappointed with the units as I had high expectations. One of the key factors that made me decide on the Deco units is the capability to expand your "mesh" network by adding other Deco devices.

Evidently, this is not the case. You can expand your WiFi but it will not have the "mesh"capability" which is really the main purpose. For the X68 I have no way to select the device for the "satellite" to connect to (source). And, even though it may be an "intelligent" decision, it does not look like that. For me, this is an actual deal breaker.

I was looking to upgrade from Google AC WiFi mesh network and found myself with more dead spots in the basement due to that. Not good.

When you say "Deco will choose the best signal source by itself", is there a way for me to see the quality of the signal each device gets from the source? 

As of right now, the only signal quality seen is the one to the "source" which cannot be changed or even tested with others.

So, in my case, it is impossible due to the location of each of the three devices. Three floors, main located in the third upper floor, and one satellite on each lower floors (Second floor and Basement), pretty much located in opposite sides of the house.

Then, what really does not make sense is that, from the Basement device, there is an "almost direct" line of sight to the second floor device. and then main device located in the third floor, almost opposite side of the house. 

Really hope it can be resolved very soon. I like the units but they clearly do not work as a mesh network and more as a WiFi extender which, don't work for me specially after the price tag on the kit. I'll have no other choice than to return them and go with another brand. 

@TP-Link 

Thanks very much....

Question, (looking to do more testing), does the "mesh" capability on the Deco X68 devices work when they are used as access point ? (I know other services like NAT and Parental Control do not but, if the MESH works in access point mode, I can still use the ISP provider modem as router and play with those settings.

Ideas?

@TP-Link 

Totally agree with that however, check these results from previous testing:

- Using only the main (third floor) and second floor devices (just two). Some of the devices I have in the basement still connect.

A- One computer (Linux computer I have in the basement running Plex) can also connect to the second floor Deco device. Speed test shows download speeds over 200+. This may be mainly because this is the only device with an 802.11AX NIC adapter. 

B- An Alexa device I also have in the basement (which only connects 2.4GHZ, can also connect but with browsing delays.

C- A Wireless Security Camera I have in the basement, can also connect but unstable connection.

Then, if I connect the third device directly in the basement (having it automatically connect to the main router in the third floor and bypassing the second floor one)

A- I have the Linux server connected to this device and the speed test drops to less than 150MB...

B- Same issues with the Alexa device

C- Same issues with the camera

So, it looks that, instead of improving, things go the opposite direction and the only thing I noticed was the source for the basement goes farther. Please note that I did not have issues with either device in the basement (security camera or Alexa device) when the Google Wifi AC1200 was used.

So, certainly something is not working properly and I notice that, when adding the third satellite, the second and third behave like a "wifi extender" and no "mesh" improvements are seen....

Not sure what issues could be affecting the third Deco, when it connects to the Main Deco because the app does not allow me to do any testing...

Also, being these units come in pairs, I have an extra one but don't want to replace any until I hear back fro TP Link on how to scan or troubleshoot the connectivity between the Deco devices...

@TP-Link 

Thanks for the reply. I ended up disconnecting the basement satellite and having everything going through the remainder two devices. Not the setup Iḿ looking as I still have some dead spots through the house but is the best one I can have for now.

Once the engineer connects to my computer, we can then troubleshoot other options.

@LER 

Hey, noticed browsing the community support site that it looks this is a very well known issue for Deco units. A whole bunch of people are experiencing the same (not able to daisy chain their units) which ends up affecting overall performance. 

What really surprises me is that they are being told that this will get fixed in the "next firmware update..." but it looks they are still waiting. 

Found topics fcoming all the way from 2020, affecting many different Deco models which don make me feel better....

Hope we can get it solved today.

Thanks

@TP-Link 

Another update.... Turning on/off the MESH option on some devices do not work. They keep jumping between different Deco devices. Issues keep coming...