Single footing size cannot be less than 70 cm.
The Complete Message:
Individual foundation size cannot be less than 70 cm. (TS500 10.3.2)
Solution:
Give the dimensions of the solid and named single footing at least 70 cm.
Select single footing, single footings.
Enter the properties.
In the general settings tab, write at least 70 cm in the Dimension X and Dimension Y lines.