When the inverter flashes a red light, it signals a problem. Common issues include overloading, grid failure, or overheating. Sometimes, temporary conditions, like shading on panels, can cause the light to flash. In this guide, we'll explain what a red light on your solar. Seeing a red light on your solar inverter can be a little alarming—but it's not always a sign of something serious. In many cases, it's just your system's way of letting you know it noticed something out of the ordinary. It is a protection mechanism — but it still needs diagnosing. The cause could be a momentary grid event that has already resolved, or an ongoing fault that will prevent generation until it's.