@TeePeeLinkSucks yeah it's pretty bad it has to be this way.  I managed to get it working again by following the plug back in one at a time.  I'm going to keep fighting with TP Link support to ger custom configuration files specifying my WAN and LAN ports so I don't end up in a routing loop that shuts off my WAN when the ports are all hardwired.  I like the speeds I am getting and the coverage across the house.  It works for my family.

However, I am definitely considering setting up my old network which is an ASUS Gamer Router which has a much better user interface and all.  I'm not sure if these devices can be configured to bridge off of my main subnet so I would probably create a route to it instead and secondary /24.  

I did get it to work though by unplugging, doing one line at a time starting with WAN.  For my 2 switches, I plugged one device in at a time.

  @TP-Link 
Still, almost a year now, waiting for a fix for my Deco M5 trio with HW version v3.0.

I am tired of resetting and re-configure my M5 and powring down my router to workaround your bug few time a week

  @dc11 given the option - I would return them whilst you can. I wish I didn't have them, but didn't find the problem in time and can't afford to junk 4 deco's - and in much honesty, can't really resell them to anyone either!

I keep hoping that an openwrt port will be completed for the deco series - as when that happens the TP-Link garbage can be removed. The HW is ok, it's just the firmware that is completely unacceptable.

  @TP-Link 

same problem here with my Deco M5.

Useless as router now that I have decided to install a home automation system.

So far it served my network nice and fast but this is an unacceptable bug, I have o report that problem to the local market so other people does not invest their time and money on these products if they are going to use them as routers.

It seems that TP-link cannot or does not want to fix that.

  @pgour agreed.  Would be nice if they can could provide the solution to manually specify LAN vs WAN ports.  So far mine has still been working since I followed the method to plug back in one at a time.  But I do not want to do this everytime I encounter issues.  @TP Link I cannot recommend any of your products due to the lack of support.  I will go ahead and update my Amazon review to 1 Star as this product does not function as intended.  If you provide a solution in the user interface to select and specify which ports are WAN vs LAN, I will change my review to 5 stars reccomend this product and the TP Link customer support.  We need a developer solution. Not offering replacement devices through RMA.