Audio not working in sequence in Premiere Pro

Hello Wise people - have you ever had the experience of importing several different videos into Premiere Pro and not one has audio in the sequence. The actual audio bar is there with no audio on it. We have checked the Codec, Audio settings and cleared the media cache and all is as it should be.  We have tried 3 different videos on an older MacBook Pro ( 6 years old) and not one has audio in the sequence. I figure it must be the machine or the Premiere Pro (Cloud) that is loaded on the machine as I have used the exact same three videos in Premiere Pro on another MacBook Pro and the audio worked perfectly. Thank you!