I have a flashing pale green ring on my Echo Dot. Maybe its yellow.
I've tried looking up what the meaning of both are. For yellow, it suggests that I have a message waiting or that I need to reconnect to my wireless network. I don't believe this to be the problem as when I ask Alexa to play messages, it indicates that there are no messages. And when I give it an instruction which requires connection the the internet, it functions, so I know it is connected.
The green light indicates "Incoming" call or "on a call", neither of which are possible with my current configuration.