Cassette sound stops

I just received my device/software today and began trying to transfer a cassette recording to my computer. The tape consist of an interview, therefore there is no pause/stop action occurring. My operating system is Windows 8. Everything seems to work well during the recording, then for no apparent reason the sound stops on the cassette. I have tried several times, but the sound stops (never at the same place). The tape is still moving but no sound is coming out.

What am I doing wrong?

How are you playing the tape and how is it connected to the computer? Model Numbers? Does the player have sound meters? Does it have a headphone socket?