Looping

I created an audio file.
I then imported an mp3 music track.
When I press play the vocal track starts as does the music track, but somehow the audio is in a 4 second loop. I don’t know what setting I clicked to make this happen.
As I said when I just have the vocal track on the screen it doesn’t loop. Its only when I import the audio mp3 track.

Thanks

How long is the vocal rack and how long is the music track?

Koz