Sandisk not recognizing audiobook

sandisk Sport Go not recognizing audible book, converted to MP3 with TunesKit. It has recognized and played other similar. I have 2.87 GB free space left.
Also some books it puts in music. Many thanks, Jane

Hi @blueboar ,

Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for best assistance and troubleshooting:
https://kb.sandisk.com/app/ask