Why am I getting a 401 Unauthorized error with my D-ID API Key?

I am trying to use the D-ID Talks Streams API to create a real-time streaming session. Here is what I have done:

I am using a Trial API Key: eWFuY2hhbzk2MDUwMkBnbWFpbC5jb20:_se9PK4VEdJrV_UJruUHM.
The endpoint I am calling is https://api.d-id.com/talks/streams.
My request headers:

{
"Authorization": "Basic eWFuY2hhbzk2MDUwMkBnbWFpbC5jb20:_se9PK4VEdJrV_UJruUHM",
"Content-Type": "application/json"
}

The response I receive is: 401 Unauthorized {"message": "Unauthorized"}.

I want to confirm:
Does the Trial API Key support the Talks Streams endpoint?
If not, what plan should I upgrade to for this functionality?