Time_stamp returning NaN if i put it in the second column

If I plot a chart in which the ldr reading is in the first column and the time_stamp in the second, it results in an error reading NaN.
COde - plotChart(“ldr” , “time_stamp”);

Whreas, if i put time_stamp in the first column, it works.
Code- plotChart(“time_stamp” , “ldr”);
Why is this so and how can I solve it?

Pls send the source code

What does that mean?

U have to send that code which u got above output.

@jindaldhruva These are built-in functions created for us to use. The parameters have to be passed accordingly. So that would have caused the error. So stick with plotChart(“time_stamp”,“variable”);
And also please do not share your bolt device name. For security purpose, and mainly never share your API key, if known then its easy for hackers to hack into your system

what is the api key?

@jindaldhruva You will get to use API key in the upcoming lectures. For now I’ll give an overview of it: API is an unique identity for yourself in the Bolt Cloud. So many people use the bolt cloud like you, how can the cloud identify you and give the response back to you? This is possible through the API key. It acts like a messenger between applications. You will learn how to use it also, don’t worry! Keep doing the course!

@nimyug18 , thanks for your kind help. :pray::pray: