CST Error "Some higher propagating mode..."

During the transient solver
The error show this "Some higher propagating modes at port 1 are not considered time domain calculation. This possibly leads to an inaccurate energy balance. Consider to increase the mode or decrease upper frequency limit."
i used waveguide port for microstrip fed antenna
Any guide to solve this problem?

Some options: First, increase the number of modes for the Waveguide and look at which frequency this mode is propagating. Maybe you can reduce your frequency span. Second, change the dimension of the waveguide!
Regards

Hi dear
but I do not know : how I can increase the number of modes for the waveguide port in CST ?
When I run the project in transient solver ,I choose all modes for solving !
Regards

When you define your waveguide, you can choose how many modes are considered for simulation in the dialog.
I think it is on the bottom right side.

I find it
thank you very much
Regards