Send POST request to HTTPS

Hello, I’m sending my post request to HTTPS page https://example.com/index.php?fc=module&module=mydemomodule&controller=display this way:

    IEnumerator CaptureScreenshotAndPost()
    {
        byte[] imageBytes = screenImage.EncodeToPNG();
        WWWForm form = new WWWForm();
        form.AddField("hello", "yellow");
        form.AddBinaryData("fileToUpload", imageBytes, "screenShot.png", "image/png");
        UnityWebRequest www1 = UnityWebRequest.Post("https://example.com/index.php?fc=module&module=mydemomodule&controller=display", form);
       
        yield return www1.Send();

        if (www1.isNetworkError || www1.isHttpError)
        {
            Debug.Log(www1.error);
        }
        else
        {
            Debug.Log("Upload completed!");
        }

    }

But getting the following error

Mixed Content: The page at 'https://example.com/index.php?fc=module&module= mydemomodule&controller=display' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://example.com/index.php?fc=module&module= mydemomodule&controller=display?fc=module&module= mydemomodule&controller=display'. This request has been blocked; the content must be served over HTTPS.

My request was to https://example.com/index.php?fc=module&module=mydemomodule&controller=display, but the domain have redirect to www.example.com, so it redirects it to the HTTP-page with www
http://www.example.com/index.php?fc=module&module=mydemomodule&controller=display