Hi Nyurons, 

I don´t know why this error appears. My project have a 1s total time and 0,005s each time step. I have done other project with 0,005 s time step, but total time up to 0,65s and i have had no problems at all. Could you tell me your total time when you had this error? 

I will try to change to 0,01s time step, but i am afraid this does not allow me to see the phenomen I am studyng (flutter).

Thank you