[Moved]CST Problem with antenna simulations

hi everyone ,
I have problem with CST when I simulate my antenna, the CST shows me warning that the accepted power is very small , the gain inaccurate . Can anyone help me please to tell me whats the problem ?

thanks

I have the same issue, I am trying to excite a helical antenna using a discrete port, the separation between the ground plane and the start of the helix is 0.3 mm the port ends penetrate 0.05 mm into the surface of both the ground and the helix but still, little power is accepted.

Any ideas what could be causing this?

Thanks