The Complete Message:
The beam height cannot be less than 3 times the slab thickness.
Solution:
Select the solid and named beams and give the beam height at least 3 times the thickness of the slab connected to the beam. (For example, at least 36 cm for a 12 cm slab)
Select the beam, beams
Enter the properties.
In the general settings tab, increase the beam width and click the OK button.
