[Bug]: Call a locally exposed web service

[porta76]

AL-Go version

8.3

Describe the issue

We are creating automated test cases for our integration solution and need to call a published OData V4 endpoint from AL. The web service is published through webservices.xml, and the endpoint is accessible externally.

Scenario
From AL code we attempt to call the published OData V4 URL using HttpClient.

Expected behavior
Since no authentication header is provided, we expect the endpoint to return HTTP 401 (Unauthorized).

Actual behavior
When the request targets the same Business Central instance (local call), the request fails before reaching the endpoint.
However, if we change the URL to an external web service, the HttpClient request works as expected.

Additional information

• HTTP requests are enabled for the extension (Allow HttpClient Requests = true)
• The OData endpoint works as expected when called from a local docker.

We would like to understand whether calling an OData endpoint from AL in the same BC instance is supported and why the request fails instead of returning 401 Unauthorized.

Expected behavior

Web service to call locally

WebServiceManagement.LoadRecords(WebServiceAggregate);
WebServiceAggregate.SetRange("Object Type", WebServiceAggregate."Object Type"::Page);
WebServiceAggregate.SetRange("Object ID", Page::"External WS Trigger API");
WebServiceAggregate.SetRange(Published, true);
WebServiceAggregate.FindFirst();
PageUri := WebServiceManagement.GetWebServiceUrl(WebServiceAggregate, ClientType::ODataV4);

Steps to reproduce

Publish an OData V4 web service using webservices.xml.

1. Create a test codeunit in a Business Central extension.
2. Enable HttpClient requests for the extension (Allow HttpClient Requests = true).
3. In the test codeunit, construct the OData V4 endpoint URL for the published service.
4. Use HttpClient in AL to send a request to the endpoint without authentication headers.
5. Execute the test.

Additional context (logs, screenshots, etc.)

If the same HttpClient code is used to call an external web service, the request works as expected.

[porta76]

We believe this is related to how the AL-Go pipeline environment runs the container, rather than being a general AL or Business Central behavior issue.

Our scenario works as expected when running locally in Docker. In that case, the published OData V4 endpoint can be reached and the request correctly returns 401 Unauthorized when no authentication header is supplied.

However, when the same code is executed inside the AL-Go pipeline, the call fails before reaching the endpoint when the request targets the same Business Central instance.

This suggests that the issue may be related to networking or container configuration in the pipeline environment. In the pipeline we are effectively trying to call a locally exposed web service from within the container itself, and it appears the container cannot resolve or access that endpoint the same way as in our local Docker setup.