We went a long time without internet at home, but have had it for the past year. I do have an Envoy, all the inverters are listed with Enphase and five inverters are speaking to the mother ship continuously. One inverter is not, but does have a nice red light glowing on it.
I get a production email every month showing what the system makes, so clearly they aren't that good at catching faults, or they have written me off for some reason. Last August, I sent a certified letter hoping to get their attention. I included all six inverter serial numbers and that one of them had a red light glowing and how long I had the Envoy connected to them through the internet. It didn't help at all.
The failed inverter was bought new in 2010, and they have changed the cable connectors (for the daisy chain cables) so I can't buy a new one off the shelf and get the solar panel back in the game of producing energy. I found that little tidbit out when I looked online to try to buy a new one, and then checked with Blake at Mr. Solar to see if they had any of the old-style cable inverters left in stock, or if there was an adapter cable so I could add a new one anyway. No and no.
To say this is frustrating would be an understatement.
I have 1050w rated PV connected to the inverters, but only 875w worth of them get power through to the wall and know of no realistic way to solve this.