Have you recently fitted it to an electric bike? They don't like to be in the vicinity of motors.
Yes I've had that problem in the past with electronic interference with things like lamps, controllers etc, especially when the battery gets low. However, this one was working fine, I hadn't changed anything on the bike and out of the blue last week it stopped working, even with all the electrics off and just spinning the front wheel by hand.
I thought it was probably just a dead battery. I changed the one in the transmitter, but that didn't help. I changed the battery in the receiver, but it still did not pick up. I took the transmitter off of another bike and the receiver picked that up ok, so it looks like the problem is the transmitter.