Simulate a Helical antenna in CST

I am trying to Simulate a Helical antenna in CST and am trying to use a wave guide port at the end of a coaxial cable to excite the antenna, is this the correct method? I am receiving the following error; Port number 1 is completely filled with metal. Maybe the background material is defined as PEC?
The background is not PEC, the waveguide is on the surface of the coax cable as shown in the image.
Has anyone simulated Helical antennas before and has any advice?
Thanks

Background material should not be PEC. Use normal material with mu and epsilon of 1 for the background material. This should be the default. Make sure your coax feed actually has a dielectric section of material to it. It looks like your dielectric portion of the port is modeled as PEC. The fact that its all the same color means your coax port is all the same material.
Also, increase the red port feed to cover the entire coax port including the outer conductor, and not just the inner conductor and insulator