The Grafana datasource JSON API does not connect to the datasource JSON API of the couchbase node.

[rmntrvn]

Hello. Grafana does not connect to the couchbase JSON API.
I installed the marcusolsson-json-datasource plugin for grafana, I create a datasource, specify the URL http://<my_couchbase_domain>:8093, turn on the Basic auth and with credentials checkboxes and enter the Administrator login and password <my_password>, I get an error:

JSON API: Cannot connect to API

There is nothing in the grafana logs on this issue. Locally, curl to the couchbase API works fine from the grafana pod too. Grafana is installed on a Kubernetes cluster.
The only thing you can catch on is that in the Chrome developer tools there is:

GET https://<my_grafana_domain>/api/datasources/proxy/7 404

Can you please tell me what could be the problem here?