Combine results in CST in one port

Hi every one,
I am simulating a horn antenna with a wave port with two orthogonal modes (to get circular polarization), the combine option in Post processing tab is not available for me. it gives me this warning:At least one propagating mode is not considered at port 1.
Can anyone help me please?
Thank you very much

Can you take a picture for this error?

Oh, Thank you so much I figured that out. It was my mistake