Grafana 10.1 API: cannot create an organization

Question

I want to create a Grafana organization through its API.

According to https://grafana.com/docs/grafana/latest/developers/http_api/org/

Create Organization
POST /api/orgs
Only works with Basic Authentication (username and password), see introduction.

Example Request:
POST /api/orgs HTTP/1.1
Accept: application/json
Content-Type: application/json

{
"name":"New Org."
}

Note: The api will work in the following two ways
Need to set GF_USERS_ALLOW_ORG_CREATE=true
Set the config value users.allow_org_create to true in ini file

Example Response:
HTTP/1.1 200
Content-Type: application/json

{
"orgId":"1",
"message":"Organization created"
}

I set up the following curl command:

curl \
-H "Accept: application/json, Content-Type: application/json" \
-d '{"name":"test"}' \
-u "admin:admin" \
-X POST \
http://localhost:3000/api/orgs

Its (bad) results is: {"message":"bad request data","traceID":""}

My /etc/environnement:

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
GF_USERS_ALLOW_ORG_CREATE="true"

My /etc/grafana/grafana.ini contains:

[users]

# disable user signup / registration

;allow_sign_up = true

# Allow non admin users to create organizations

;allow_org_create = true
users.allow_org_create = true

Note that any ";something" is a Grafana default that should not need to be set, from what I understood ...

Any ideas welcome.