I can only record via microphone, NO joy on the speakers

Hi all,

I downed audicity yesterday and I followed all the handouts I could find on the web, yet I only record speach from the microphone (like arearecording, all the people around me talk and it gets recorded perfectly) but music by the speakers (like youtube music) is not recorded, what is wrong?

Please help me out

greetz, GERT
The Netherlands