WebGL Build WWW class : Unknown Error

Hello,
We have an Web Application created by Unity. We’re trying to access a remote server using WWW class provided. When I try the WebGL build on my local machine, it can communicate with remote server. However when I put the WebGL build on the remote server (which will represent our Web Application, simply where the index.html is ) the communication gives error.
Here’s the code:
IEnumerator ss() {

		WWWForm form = new WWWForm ();
		form.AddField ("name", "hello");

		url = "remote.server.ip.address:port";
		WWW www = new WWW(url,form);

		yield return www;
		if (www.error != null) { 
			Debug.Log ("Error is not null" + www.error); 
			theText.text = "Err:" +www.error;
		} else {
			
			string formText = www.text; 
			Debug.Log ("Response: "  + formText);
			theText.text = formText;
		}

	}

And error www.error returns an UNKNOWN ERROR.
What may be the cause? I’ve seen some topics that says it may be related to CORS. But I am not sure about the real reason behind this problem. Could you please help?

Thank you.

Did you deal with it ?