Get PowerBi Audience users via REST API?

Hi there is an undocumented method but i cannot seem to get it working 

if you make a get call to 

https://wabi-north-europe-l-primary-redirect.analysis.windows.net/metadata/appmodel/apps/WoprkspaceORGroupID?requestDataType=7&access-control-allow-credentials=true 

but you need a bearer token and our bearer token that can access other PBI api does not work.

must be a permission issue .

but if you copy a bearer token from when you log in to power bi via f12 developer mode it does work.

i get a json response with the app and audiance name and members .

if anyone can help me how to get the correct bearer token i would appreciate this.

below is an extract