Hi Huikang, this is a little late but this type of error can mean that one of the signals in your model is diverging to plus or minus infinity or is otherwise changing too rapidly based on the solver settings: https://www.mathworks.com/matlabcentral/answers/451575-what-does-the-nonlinear-iteration-is-not-converging-error-mean
I would recommend using constants instead of the ROS message to verify that your model is still working correctly. If it is, then plot all your ROS message inputs and determining if they are diverging to plus or minus infinity or changing too rapidly.
