Audio issues during a meeting when using MacBook

[KerryL88]

Since buying a MacBook I keep having audio issues. My audio tests fine before a meeting but when someone enters the meeting they can't hear me and I can't hear them (the video is fine). I tested it with my daughter a few times (via mobile and her Mac) and every time it was fine so I thought it was the person specific (their error). However, this has happened three times now. Has anyone else had this issue? Thanks