The chances that your brand new Canon camera is malfunctioning are very, very small. (That coming from a Nikon user.

) I just now opened the manual for your camera and conducted a search on "busy." That signal is displayed in five or six different situations. If you conduct the search and read about those situations, it's likely that you'll realize what caused your situation to occur.
By the way, keeping the PDF of your manual handy and available will almost always be the easiest and fastest way for you to figure out stuff that is otherwise inexplicable, especially while you are new to your camera. Even though I have been using my camera more than six years, something happened a few months ago that I had never noticed and didn't know about. I looked it up in the manual and the problem was immediately solved. That explains why I always keep my manual on my laptop when I travel and it is always stored in my DropBox account, allowing me to use it anywhere I have Internet access.