Connection problem with RemoteXY

Hello All,

I am a fresh programmer trying to write small codes by using Arduino + RemoteXY.
I am using a NodemcuV3 ESP8266 board and I was able to upload a simple sketch into it. When I tried IOS phone or Android phone, I am receiving the same error : "The operation couldn't be completed. Connection refused.".

Can you please help me?

Thank you for your kind assistance,