[Gmsh] Error issue

[koh kelvin]

Hi,
I have encountered an error. I have done the 3D meshing completed. Everything looks fine. But after save it as .msh file and re-run the 3D mesh, the error appears.
Error: No tetrahedra in region 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Initially, I was intended to import file to OpenFOAM. Error appear too. So I decided to open the msh file in gmsh to check. 
I don't understand. the geo file shows no error at all. Save in msh error prone.
I need your advice to resolve the issue urgently.
Many Thanks.
Regards,Kelvin Xu

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://onelab.info/pipermail/gmsh/attachments/20181017/c89adb2d/attachment.html>