@MelbourneMaker I am going to leave troubleshooting to TP-Link senior engineers, now that they are involved. When they find where the problem is, I'll appreciate you posting their findings here....

@Thackers Thackers wrote So to clarify. 1. Leave virgin router in router mode but turn off wifi. 2. Hard Wire all decos after my cisco network switch in various rooms in house. 3. Set each deco to...

@Thackers I would recommend X20 or X60s, correct. If you have Ethernet cable in each room where you want to have excellent WiFi, and if you can place Deco there so that it is seen from every corner...

@MelbourneMaker I have somewhat simpler home network configuration, with just ISP Router, and Deco M5/M9 mesh running in Access Point mode. When I deployed my Deco mesh, I wanted to assign static IP...

@TheProphet M9 is more powerful unit than M5. Deco M9 will provide better WiFi coverage. Considering it is corners of your house that get weak WiFi signal now, it would make sense to spend more and...

@Thackers Replied to you here: https://community.tp-link.com/en/home/forum/topic/538184?replyId=1053928