Error sending data to Azure IoT Hub

[mshaz]

I have an issue sending data to Azure IoT hub. I could only send 3 parameters Temp, Humidity, AirQ.
When i added the 4th line Pressure, it got disconnected.

Here is the error
msg : string[93]

"Invalid JSONata expression: Argument 1 of function "number" does not match function signature"

The data came from thinkspeak.

Thank you

[bakman2]

field3 is null so running a jsonata function over it ends up with an error.

[mshaz]

How do i handle the nulls?

Thank you