You need to give IP address of ThingWorx cloud instance, not the WiFi LAN's IP.
You can find it by pinging TW instance from your PC. TW instance is something like xxxxxxxx.cloud.thingworx.com. Get it from your browser URL.
Also you need allow REST calls in TW. For this,
-->Go to Systems --> SubSystems--> PlatformSubsystem. There click on configuration, check for allow REST API and Uncheck Filter Content-Type.
Hope it helps.