MP3 Walkman Model NWZ B172F Saying "Verbinden M.USB"

Hello,

Please Help I'm still using this MP3 Player Walkman model NWZ-B172F 

Whenever I connected it to the laptop It said "Verbinden M. USB" I don't know what it means, When i charge it to a adapter, it wont charge the battery but will play music. I been using this Walkman since 2013.