Simulink error with integrator

I am trying to simulate a mechanical dynamical system and I am getting hte following error :

Derivative of state '1' in block 'HW3que2d_least_sq/Integrator3' at time 0.0 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)

What should I do further to remove the error.

I have also attached my simulink model.

Any help would be really appreciated.

[Renato SL]

In case you haven't found any solutions, maybe this discussion could help (link).

I cannot open your .slx since what I have is R2017b, but what I can suggest is not to use zero as the initial condition of the integrator. In case it has to be zero, I suggest using a very small number, like eps.