Error water level in canal is above the height of the canal

I have got the following error while running a simulation:
The water level in canal 'st_3062l1' is above the height of the canal. Perhaps due to too long time steps or too large inflows (inflow hydrographs) in nodes.

Could you please suggest where should I look to fix it?

Thank you in advance

Hi Zoi, 

This error indicates that your simulation may be unstable, reducing the time step will help you improving the stability of your model.