When you click Test step in the HTTP Request node there is a POST request going from the n8n front-end to n8n back-end, indicating that n8n should make a GET request to the domain you set.
Basically, you cannot view the request in the Network tab of your browser’s Web developer tools. That tab will show the browser’s own requests, not n8n requests.
However, n8n people knew that for debugging you’ll need to have access to what n8n sees, so if you switch to the Console tab in the Web developer tools you’ll be able to see logs about the GET request going to apibox.erwaima.ai domain, with the associated headers.