Derivate of state is not finite error

Hello guys,

I'm having the following error:

An error occurred while running the simulation and the simulation was terminated.

Caused by:

Derivative of state 'Plant_Thumb_3.R1.Velocity' in block 'Model/Plant/Thumb_3' 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)

How can I solve this?

Thanks!!!