You have got to give us more to work with. What is the car, Coupe or Roadster?

Any Roadster that does exactly that is probably telling you of an issue with the top - you dont' have it all the way put up or all the way down. OR, the top module THINKS you didn't put it all the way up or down - that is, the cycle did not complete. In nine years of owning three Roadsters, this has happened to me a handful of times. Usually, you can put it thru the cycle once and make it go away.

Now, if the headliner sensor, bow sensor or lid latch sensor is bad, it will beep at you until you get it fixed.