Audio track shows on session, but no sound from it?

[rockguitarist1255]

This is a little odd. I have some audio tracks of guitar, and when I first open the session, the audio from that track plays. After a few minutes though, when I play back the session, the guitar tracks don't have audio. They still show up on the session, and the audio meters still function, but no sound comes from them. This only happens with some guitar tracks also. The other guitar tracks work, while the ones I talked about don't seem to work. I checked and made sure no mute or single was also on so I don't know what is wrong.