This is interesting because up until a couple of years ago I would have agreed with @Izabela. Now I have a slightly different view…
For whatever reason your recording has audio gaps/drop-outs in it. Now depending on what that actual source material is, it is sometimes possible to repair the drop-outs so that there is an audio signal present where the drop-outs were.
A few factors will decide if the file can be repaired successfully so before I get into how it could be done, would you mind sharing the file as an high quality MP3 with us for me to just try and see if it is possible to repair.
Thanks Ian! That’s very interesting - certainly following up on that as I am interested to see what you come back with, are you using any external restoration software?