"We have had the conversation. He gets it. He knows it, and we have gotten no sign from anyone on any level that there is any issue," Cuomo said. "It's his confidence that matters – and our contractual protections. A contract is a contract."

But there are ominous signs. Tesla's solar installations fell by 17 percent to a five-year low during the fourth quarter. Its solar deployments last year were 62 percent less than they were just two years ago, when it was the unquestioned leader in the residential rooftop market with a market share of around 33 percent. Today, Tesla is No. 2, and its market share is around 9 percent, according to analysts at Wood Mackenzie Power & Renewables.

Tesla doesn't expect the decline in its solar business to stop right away, either. The company said in January that solar deployments would drop even further during the first quarter to another post-2012 low.

Tesla also has trimmed its sales channel for rooftop solar. To cut costs as it ramped up Model 3 production, it stopped selling solar door to door in favor of online sales and adding solar displays at Tesla stores, with the expectation that there would be a lot of overlap between the company's vehicle buyers and its solar customers.