@ngiovas 

If the power goes out the modem probably is not recognizing the router correctly. If that is the case, leave the Deco powered on, and only power down the modem, then boot the modem back up.

If there is a second Etherent cable connected to the main Deco, disconnect that as well.

@Tony ,

thanks,  I have tried that and it doesn't work.  I have hit the reset button, unplugged it, disconnected the second ethernet cable.  Nothing seems to work.  All previous routers I have had recovered on their own after a power outage.  With this one, all three units have a red LED and will not recover.  The only solution I have been able to come up with is to do a factory reset.  I would have thought that at least the wifi connection would come back up without an internet connection, but that doesn't even happen.

I should have been more clear in my original post - I not only lose internet, but the wifi does not come back up without a factory reset.   The app tells me that it cannot connect to the deco. This happens on all three units.

@ngiovas 

Ya, at the very least the Wi-Fi should still be broadcasted.

Swap the main Deco with another of the satellite units, the LAN ports on the main Deco may be the problem.

@Tony try changing the ethernet cords and the ports from the modum to the pods and

make sure the internet is coming in by connecting a computer to the modum directly

@ngiovas Any updates to this? None of the approaches are working. In my case, the mesh network went down after I power recycled the router. 

@SurfinAsh after contacting tp-link several times and support telling me that this is totally normal, I finally gave up.  I returned everything to Costco and picked up a set of 3 Orbi mesh network devices and couldn't be happier.  They are WAY better than the tp-link.  Range is much better, speeds are way higher and they re-connect after the power goes out.  Imagine that.

Sorry I couldn't be of more help, but it was so frustrating to have tp-link blame everything but the device.  One agent just kept telling me "but you got them to reconnect to the network didn't you?  then they work as they should".  Yes, spending over an hour resting a device after a power outage is perfectly normal.  I highly recommend that people avoid tp-link and go with a quality brand with real tech support.

I just found this thread, after having a power outage over the night (which happens quite frequently where I live). 
 

All the units are blinking red. And it seems the only way to make them work is to set them all up from scratch (I have 6!!). Even opening the app, the network is not there anymore, it takes me to the "get started" screen. 
 

It takes quite some time setting them all up again, like ~1h (yellow light, wait, turning red, wait, have to hard reset, wait, blue light etc, sometimes not working so have to repeat). But also, I am not allowed to use the same wifi name despite turning them all off ("network already exists") so I need to set up a new name - meaning changing wifi and password on all devices including TVs, surveillance cameras etc....! 
 

Please tell me there is a fix in progress for this, if not I will have to change the whole system as well :( especially for the surveillance cameras I am not comfortable with the wifi being out all night just because of a short power outage. 

@Tony 

this worked for me.

@Lise Agreed! So frustrating! 
I've sent them mails but they keep giving me tips on what to do to solve it, but I've tried EVERYTHING! And the only thing that works is setting it up again. 3 decos, includng the one in the flat that I rent out.. This is not good enough! When will you see that this is a fairly common problem without any good solution TP-people?!