FEKO Feeding Problem (not a free edge)

I am trying to simulate an end-fed dipole antenna. its just a two layers antenna, a substrate and an end-fed dipole.

Check attached image for the design.

The red line is the feeding line. When I simulated it in free space without a substrate, it worked fine, but when I added a substrate layer, I couldn't add a wire port to the feed line, it gave me an error message: The edge Union2.Edge2032 is not a free edge

any idea how to fix this problem?

Thanks