In order to get resource that TRUE Connector offers, you need to send ArtifactRequestMessage to B-endpoint.
We can query the resource with ArtifactRequestMessage:
Multipart form - Artifact Request Message
curl --location -k --request POST 'https://localhost:8184/proxy' \
--header 'Content-Type: application/json' \
--header 'Authorization: Basic aWRzVXNlcjpwYXNzd29yZA==' \
--data-raw '{
"multipart": "form",
"Forward-To": "https://ecc-provider:8889/data",
"messageType":"ArtifactRequestMessage",
"requestedArtifact": "http://w3id.org/engrd/connector/artifact/1"
}'
If Usage Control is active (in Docker scenario), our access to the resource will be denied.
If you recieve other response than RejectionMessage:
1) Check if Usage Control is enabled.
2) Check if there is an old policy existing in /policies folder. You should delete previously presisted *.policy files in this folder and restart Docker.