What happened to one of my sound channels?

[holden94]

I finished my video and everything worked fine.  But I needed to do a tweak and for some reason one channel is not giving me any should, while the others are working just fine.  On the timeline, that channel looks different but I can't figure out why or what it means.  I sure would appreciate some help.

[RobShultz]

Those stripes usually mean insufficient media. You might want to double check the file to see if the sound is still there on the original file.

[Ann Bens]

FAQ: What do I do when I see diagonal lines on clips