Send POST request to HTTPS

Hello, I’m sending my post request to HTTPS page 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("", form);
        yield return www1.Send();

        if (www1.isNetworkError || www1.isHttpError)
            Debug.Log("Upload completed!");


But getting the following error

Mixed Content: The page at ' mydemomodule&controller=display' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint ' 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, but the domain have redirect to, so it redirects it to the HTTP-page with www