My Carwings stopped entirely on Septemver 21, 3 weeks after I took delivery. I ignored it for awhile, because I live in an area with poor AT&T coverage (Laurel Canyon in Los Angeles). But when Santa Monica Nissan closed, I decided to check out Miller Nissan's service department and see if I could get Carwings going again.
I made an appointment and arrived a few minutes early. The service writer was a disappointment ... "What can we do for you today?" "My Carwings doesn't work." ".... ummmm ... What is Carwings?" I asked her whether I could talk to the Leaf specialist. She said "Any of us can write up a Leaf." So I politely asked to speak to the technician. She went looking and returned with the shop foreman. He took a look, and I demonstrated the problem ... hitting "Update Stations" always produces a "Cannot Connect" message, even though the dealership is located in what should be a good signal area.
He kept the car for a couple of hours; apparently disconnected the battery for awhile, and said he too some pictures of the display to send to Japan (nothing odd that I could see in the display, and the firmware diagnostic said it was current, according to his manual.)
They're supposed to call me when they know something.