I have the TP-Link Deco M9 Plus - 3 unit set. I currently have it connect in AP mode and two of the units are always blinking red and the unit connected to the internet is solid green. I currently have a computer connected to one of the units and I'm getting a decent connection, but every so often it seems like I drop connection for a short time then it comes back on. I feel like this is because 2 of the units are flashing red. 

When I look in the app it shows all of the units are connected and working fine. 

I have the latest firmware installed and the units are on 2 floors in a triangle pattern.

Cable modem--wired cable--Main Deco(first floor)

                      )))wireless((( slave Deco A( second floor)

                      )))wireless((( slave Deco B (second floor)  

I have tried switching the Deco's around to see if maybe it was just one of them having an issue, but no matter what one I connect to the cable modem it is always green and the others flash red. 

Thanks in advanced