To diagnose whether you used the correct operating point for linearization, simulate the model at the operating point you used for linearization.
The linearization operating point is incorrect when the critical signals in the model:
Have unexpected values.
Are not at steady state.
To fix the problem, compute a steady-state operating point, and repeat the linearization at this operating point. For more information, see Compute Steady-State Operating Points and Simulate Simulink Model at Specific Operating Point.