Unfortunately, since Enecsys went into administration, you cannot claim on the warranty; however, all is not lost.
Most homeowners insurance covers power surges and as I have see from the systems that we monitor, power surges are the most common cause of failure by the inverters, followed by water ingress.
So, lets say you have 20 inverters on your roof. They were guaranteed for 20 years. This means that probably 90% of the inverters would last 20 years. And lets say that you installed your system 10 years ago and just noticed that 2 inverters are no longer reporting. Roughly speaking, the probability of 2 inverters failing in 20 years in a given batch would be 1 in 100. But its only 10 years so it is even less likely that 2 would fail.
This means that is should be possible to claim on your insurance for the cost of the repair. Of course there is a catch - to prove that it was a power surge that caused the problem, means that you have to get the inverter off of the roof and have a look and that usually means scaffolding. But this will usually be covered if it is a power surge.
If it is a power surge, when you get the inverter down and open it up it will look something like this:
The next issue is the repair. Do I replace all my inverters or just the faulty one? Well, that is up to you, the installer will need to guarantee the installation for 10 years. Don't confuse that statement with the guaranteeing the parts. New Old Stock parts are available and, as long as they haven't been modified or used, they should be fine for the insurance company. There are some people who claim to have 'improved' the inverters by modifying the software / hardware. Unless the modifications were UL or TUV tested don't touch them. Of course you could always try to have the whole system replaced. Some clients have had success with that as well.