Error: There are bars for which the code check did not succeed. Object reference not set to an instance of an object

After a steel verification , you get the error

Solution

The design of custum cross-sections (also called combined sections or Section Utility profile) is only supported for Eurocode 3. If you select a different standard in combination with custom cross-section, you’ll get the error above.

The standard for steel design can be changed using the menu Analysis > Steel Design Code.