IP addresses that start with 192.168.x.x are on your local network. Since Node-RED runs inside your network, probably on a Raspberry Pi or something, it is able to access those addresses.
Losant has two types of workflows, cloud and edge. I assume you’re referring to a cloud workflow based on the error message you’re receiving. Cloud workflows work quite a bit differently than Node-RED’s local workflows. When you try to use IP addresses that start with 192.168 in a cloud workflow, you’re now referring to Losant’s own network, which is why they’re blocked.
Our Edge Compute functionality does allow you to do the workflows you’re attempting to do. Those run within our Edge Agent, which is installed locally on your own computer - a Raspberry Pi works great.
The advantage of our Edge Workflows and Cloud Workflows is the seamless interaction between the two. If your goal is to read sensor data and store it locally in a json file, I might recommend sticking to Node-RED. Losant really comes into play when you’d like to involve the cloud into your solution.