I've just gotten a new IPhone and when I make a call it gives a busy signal. How do I fix this?

Well, the number might be busy.

But first, is it a normal “busy” with one buzz per second, or a “reorder” (also called a “fast busy”)? For a Reorder contact your carrier; your account is not set up correctly.

Please explain further when you try to make a call? Cell phones don’t have a busy signal. Is the problem with just one number or all numbers you try to call?