M9 Plus randomly looses internet (light turns red)

@smatlock 

I would look at swapping the Ethernet cable being used from the main Deco to the modem. 

If the drops happen in a pattern where you can predict them, you can look to have a computer directly connected to see if the drops still happen. It might not be a practical solution, but can be tried if possible.

If you happen to have a spare router, use that to see if the drops happen. If not, then it could be a problem with the Deco units.

@smatlock are you using Ethernet backhaul? I had the red light issue, and fixed with the solution below. I just replied to another post so I'll just copy and paste this.

I had a problem with the M9 plus and Ethernet backhaul. It turns out both the dlink and Netgear switches I was using didn't support forwarding some type of specific control packets, which resulted in a reboot loop of the main Deco. Luckily I had a TP-Link switch laying around that it ended up working on

@Tony 

I did swap the ethernet cable and initially it didn't appear to make a difference.  However, whether due to the new cable or just the magic of computer issues, the problem did clear up in a few days.  And, knock on wood, hasn't returned in the last couple of weeks. 

Thanks for your help, 

Steve

@Steve_______

I wish. It seems like that should improve performance.

@Tony Wow, thank you...I spent three hours trying to fix a solid red light on my M3. Did three reboots AND resets, nothing. Then tried the videos instead of the written tips on the app (which had different and more detailed info) and got it to work. Then later, I had to reboot my modem and it turned the M3 red again. This time NOTHING worked (another three hours!). In desperation I did one last disconnect and unplug of everything, swapped the Ethernet cable, and it worked! Light is lovely bluish-white and the network is online.

(Though I have been afraid to even open the phone app again for fear it either won't connect or will screw things up, LOL.)

Gotta love the low-tech solution! Hope it holds up.