Using Maocaster 2 to record podcast - aux music not being recorded

We are using a Maonocaster 2 to record a podcast. We used an earlier version of Audacity to record with an older lap top. NO Problem. Buy newer lap top , use the Maonocaster 2 with a newer version of Audacity, it will record the two voices fine, but the background aux music is not being recorded. The Older lap top is getting older week by week, I am afraid it will malfunction before I can figure out how to get the background music working on this new lap top. Looking for any suggestion.