I'm modelling a gas turbine combustor. In the realizzable the unstructured grid for a volume of the combustor GAMBIT give me the error

ERROR: Volume (Number volume) could not be meshed without face(s) successfully meshed

I don't understand it. What can I do? Thanks

one of your surface has a bad mesh quality. Check in the transcript window, where the surface meshing has failed. you should have an warning before you get your error