HFSS port boundary problems

Hallo,

when solving "ports only", i always get the error message
"not possible to create correct port boundary, may be due to incorrect material settings in the port face"

Whats wrong.
It doesnt matter if I use lumped or waveports.

any ideas.

It is a differential planaer strip waveguide (parallel MSL).

problem solved.
it was an geometry problem.
Just exporting and importing (again) fixed it.