Do you have coupled walls in your simulation? I think I've seen this message before when I tried to connect two surfaces in a coupled wall which weren't geometrically identical.

Good luck.

Dear leicher, my simulation axisymmetric 2d vertical tube. its a simple geometry.

What about symmetry planes then? Do they match, both in terms of geometry and meshing?

If the model works with a material injected, you maybe dont have applied the injection correctly. In my case, i later changed the name and properties of the material I firstly injected and as a result it did not keep the exact position from where it was injected. As a result there was no material injected, practically.