I purchased a Devolo Dlan 1200 with two extenders. They work perfectly well. I then needed another two outlets and was advised by Devolo to purchase the Dlan 500mbps extenders to plug into the outlets I needed. This I did. For about 3 days they seemed to work perfectly well and then one of them started to alternate between green and red on the home button. The other home button constantly flashes green. I am getting no network being picked up now on either of them. I have reset them, rebooted the whole system but still the problem is there. Is there any advice someone can give me re what to try next?