Well, if you don’t mind, you can convert Audible AA/AAX audiobooks to MP3 for playing. And there are a lot of Audible audiobook converters in the market, you can try them yourself. Well, I would recommend you Tunelf Audio Converter! It works efficiently on my computer. I like it most because of its powerful conversion speed and lossless audio quality guaranteed.
I have met similar problems with it. But I have tried to use Audible Converter to change the audiobook file format for several months. It helps me convert mp3 files to AAX farmat and upload them to my Audible library! I have tried different converters before, but I recommend AMusicSoft and it worked. There are no guarantees for you that this method will work, but it’s worth a try.