Hello,
I had the same problem today. As written in the I/O file, the AirflowNetwork object with "SurfaceAvarageCalculation" option in the field "Wind Pressure Coefficient Type" only supports simple geometry (rectangular or squared ones). If your geometry/envelope is different from it you should use the option "Input" which will require all the pressure entries to this building you are modeling.
I hope I've helped you.
Greetings,