Not elligible for basic license?

I'm running Elasticsearch 7.8 in docker in a manner similar to here: https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html

I'm not sure why I am getting {"eligible_to_start_basic":false} when I check the basic status.
If I try to start a basic license I get {"acknowledged":true,"basic_was_started":false,"error_message":"Operation failed: Current license is basic."}.

It looks like an authorization error. Is there a step by step guide to get this going? The feature I'm trying to enable is the dense_vector field.

What do you get if you run the get license API? Is it possible you can not start basic license as it is already present?