that message is often when you use to high Courant noumber or order of equations at begining. Try to increase "stability" of your solution by many iterations at lower parameters and then increase the parameters.
This is the sign that your solution is diverging. You can ignore the message if the number of cells where it crosses the limit is just a very small fraction of your total number of cells. If the cell count is significant, you can try doing this
1) Refine mesh where you expect sharp velocity gradients
2) Reduce the relaxation factors
3) Reduce the time step size and increase number of iterations per time step if you are running a transient case.
4) Also check the applicability of the turbulence model you are using for your problem.
In my opinion, keeping above suggestions in mind, you should consider boundary conditions too. Because of setting reasonable boundary conditions other parameters will behave in range accordingly.
Check your mesh (especially near corners or edges) or boundary conditions (at outlet). Above message is created by ANSYS when the ratio of turbulent viscosity and the laminar viscosity exceeds 1e5. Is there any outlet in your geometry?? probabaly thats where this backflow is happening. let the simulation run and it should disappear after some iterations.
if not u can reduce URF or u can goto soluiton control/ limits/ max tub vis and add few zeros but All this is not recommended and will effect your results.