How to call iflow with a p-user.

Hello everybody,

I have a question regarding the p-user, which can be created in IAS. Normally we call our CPI Iflows with our s-users credentials via Basic Auth. But is it possible to use the p-users for this option? I already tried to assign the p-user in the Cloud Platform Cockpit (security->Authorizations->Groups). But, when I start a simple get request via Postman I get a 401 error.

Can anyone help me solve this problem? How do I get a p-user to communicate with the endpoint of my Iflow?