Error in modeling a fluid flow and heat transfer in a 3D box

Hello COMSOL Users and Sir Amir Fadil and CFD Experts

I am trying to simulate a 3D NITF Problem by heating up the air inside a box and observe the thermal transfer and fluid flow.
The material properties of the air is composed of piecewise and analytic functions.
However, an error occured as:

''Failed to evaluate variable Jacobian.''
- Variable: pA
- Geometry: 1
- Domain: 1 2 4

I tried the same set up and a different fluid (WATER) with material properties similarly composed of piecewise and interpolation functions and there was no error.

Could somebody help me out on this, please.

Attached is the file.

Thank you very much.

Jonathan