Netgear Nighthawk AX40 and TP-Link Powerline adapters

[dualloop]

Hi,
I have been tearing my hair out over this.

I have a Nighthawk AX40 which has a TP-Link Powerline adapter plugged into it.

This feeds an internet connection to 2 wireless TP-Link Powerline adapter (the walls here are very thick) at the back of the property.
I also have a 3rd non wireless one for the Sky Q box as it refuses to sustain a wireless connection.

The issue that I have is that when the adapter is plugged into the router, it causes the internet to drop for all devices.
It doesn't happen straight away and can take between 5 - 15 minutes to occur.
I have reset the powerlines, reset both the router and modem to factory with no joy.
When the connection drops, I cannot log into the router's interface to see what is going on nor can I log into the powerline interfaces.
It seems to be a conflict that is created when the powerline is plugged in but I cant see where it is occuring.

Can anyone shed any light on this as without the powerline adapters, there is virtually no internet access at the back of the property.

[plemans]

are you able to log into the router over wireless and access it? 

[dualloop]

Nope, no wireless access either

[plemans]

have you investigated what happens when just the 1 is added? And if it stays stable, add another one or switch to a different one? Might allow you to see if one of them is injecting interference or causing an error or loop.