Can't hear PowerPoint narration

I received a PowerPoint presentation to review that has audio narration on it but when i play the slide show I can’t hear it. I tried looking it up on the help menu but got no answers (maybe I used the wrong key word). I see the speaker on the bottom right corner, so how do I get it to play? Thanks in advance for your help guys

Have the same exact problem. Don’t know why audio won’t work though.