Try without the /n8n and /workflows parts of the path. Unless you have explicitly configured n8n to run in a subpath, it would normally be http://hostname:5678/api/v1
If you are connecting within the same docker environment, try http://n8n:5678/api/v1 (assuming the n8n service is named “n8n” in docker-compose.yml).
Or, if from the same n8n instance (to itself), try http://127.0.0.1:5678/api/v1