I have 3 inverters from SMA. All installed in 201...

I have 3 inverters from SMA. All installed in 2016. 2 have not had problems. However, the largest has been replaced 3 times. We have waited approximately 3 weeks so far on our 4th inverter. It is a Sunny Boy SB7.7-1sp-us-40 and has failed the last two times during peak production causing us to loose a significant amount of production. Reputable installer. Says they have had problems recently and are trying to find other inverter companies to use. I emailed SMA a week ago as of 8/25/2020 and still have not had a response. Very frustrated.