Error while updating mesh
 

Hi everyone,
I have been trying to create a mesh for a u tube heat exchanger with grouting and soil materials which I was able to create, however while updating the mesh I got an error as follows " error updating cell mesh system in system mesh". Can anyone help me with that

Thanks in advance

I have no idea but your mesh looks very weird. Why this do you make a non-conformal mesh and use an enormous change in cell size over various volumes? I can image Fluent doesn't eat it.