Question on modem

Good morning! I am not realy tech savy, so please forgive my question if it seems a bit simple or basic. I just got the CM400 cable modem to use for my internet with TWC. I have everything working just fine but I have a flashing yello icon on the front of the modem that I was wondering what it is for. Why is not a green steady like the other 4 light on the front? Thank you...anyone that can help me. I have not seen any paperwork that shows what any of the lights are for. Thanks again!! :)