Hmmm that’s super odd I just tested in Postman myself, adding the audience param in the “Token Request” section and it’s working as expected. Can you double check that the audience you are passing is the exact same as the API Identifier listed for the API you’ve registered in Auth0? Additionally, it might be worth trying to cURL outside of Postman to see if that works.
@tyf firstly, please don’t apologise for the slow response. I really appreciate your help.
Secondly, adding the audience to the Token Request section as a Request body parameter did mean I got back a non-opaque token. However, my API won’t accept it as it says it has the wrong audience. I am going to create a new topic about that, and I will link to it here.