How could I analize this filter ustrip? (URGENT!!!)

I want to use coaxial with the next model. If I analyze the same filter with waveports (using rectangles with the correct dimensions) the result is correct. But if I use Coaxial (like we can see in the model) the result is wrong. why?.
I don't want to change the dimension of the box with a probe introduction. What can I do?.

Thanks and Regards.