Single footing thickness cannot be less than 25 cm.
The Complete Message:
Single footing thickness cannot be less than 25 cm. (TS500 10.3.2)
Solution:
Give the thickness of solid and so-called single footings more than 25 cm.
Select single footing, single footings.
Enter the properties.
In the general settings tab, write at least 25 cm in the "Height at column edge" lines.