port memory exception

I am trying to use CST MWS 5.0 to simulate a spiral inductor with lossy substrate and non-perfect conductor. I got a fatal error with a message that "Calculation is aborted due to port memory exception. please reduce number of ports or simulation duration." Anybody knows what it means?

Added after 5 minutes:

hm.... while writing the above question, I figure out the reason: the bandwidth has to be increased to reduce the duration of input pulse, so that it doesn't need to store a too long array for the excitation. Thanks for your attention!

HI loucy
I think you shuould post the model and we can help you to check it.
It is necessary that there are more than 3 even mesh toward the wave transmitting direction.
In addition, you can check you ports dimension to confirm them according to request.
Regards!
caocao