Recently I bought a new iPad 4 and a "lightning to sd card reader" from apple specifically for the iPad. Today I wanted to transfer a video and a few pictures that I had put on it to the iPad but when I plugged in the sd card I was prompted with a message saying "this accessory is not supported by this iPad". This wouldn't have been such a surprise if I hadn't already used the lightning to sd card reader to upload numerous videos and photos to my iPad. Any idea what might be wrong?
Also, I have already tried turning the iPad on and off, and removed and inserted the transfer cable many times.