HTTP Error 204, while trying to delete user from AppStore connect Test Flight, using RestAPI

Question

When I try to delete an existing user from TestFlight, I receive http error 204 (no content), what does this mean? I am sure my-user-id is existing in TestFlight, I got it via API.

curl --location --request DELETE 'https://api.appstoreconnect.apple.com/v1/betaTesters/{my-user-id}' \
--header 'Authorization: Bearer my-token'