@pemu 

I have similar issue of wifi dropping by my newly installed Deco X60 (two days ago). The Deco app tells me "Something went wrong with the Cloud service". After seeing this question, I tried restarting multiple times, it didnt help. Then I reset the base unit it didnot rectify the fault. The tried resetting base plus two satellite units it didnt help either.

I swapped the units -made one of the satellite unit as Base after resetting. This step allowed the base unit to work and one of the satellite unit to work.

It appears the original Base unit, which is now a satellite that gave the problem is not connecting to the Base unit. I reset this (now) satellite unit and it changes between yellow solid and red solid.

Does it mean this unit is malfunctioning? or what would TP-link recommend doing to address the issue.

Thanks

@UShankar same issue. Units have been working for months. Now showing white (on P9s) and green (on M5s). But no Internet service. ISP is fine. 
 

cannot use the Deco app and it just states "something went wrong with the cloud service". 
 

I am close to throwing this junk out the window and buy something with better software and support. 

@TP-Link_Deco 

I'm having the same issue. I just bought my unit after dealing with outages with the Orby and I'm having even worse issues with this TP link. I just hook it up and everything was working fine for 15 minutes and now I get the constant blinking red light on the main unit. I have turned it off reset it reset my modem deleted the app reinstall the app and tried everything I know and still no luck. I can't seem to find a mesh unit that will work without multiple problems. Any ideas? 

@Jeromy 

I ended up solving the issue by doing the following:

1. Changed my "Main Deco" to another unit and connect that unit directly to my mode.
2. Remove the previous main deco that was connected to my modem.
3. Hard reset that previous main unit.
4. Then add the removed unit back to my network.
5. Connect the added unit to the modem.
6. Change the main deco back again.

This is not easy as the Deco app often fails to connect to the Deco cloud.  But if you perservere it might work.  But for sure, I would not buy TP-Link again.

@TPLink Why is it even necessary to connect to the cloud service to use for the home network? 

@TP-Link_Deco 

Do the answers to these questions really matter, If the cloud service is the one with the issue? What is the "cloud service"

 He could have 2 or 20 P9s. Comcast or AT&T. 10ft or 20ft apart. Dropping every night or every hour

I just installed this X60 system TODAY and it worked for about 6 hours, now I have no wifi and I cannot connect to cloud server????  It suddently dropped out and switches from red to a yellow/green flashing.

The whole point is to have reliable wifi and I am very frustrated.