Error: There are bars for which the code check did not succeed. 10: Automatic calculation of effectieve properties for section “…” not supported

When you run the steel verification on a profile, you get the error:

Cause

• Diamonds cannot calculate the effective properties for an CHS-section of class 4.
  On top of that, thin walled CHS-cross sections can be seen as a shell structure. EN 1993-1-6 defines the strength and stability rules for shell structures. Diamonds does not support this part of Eurocode.
• Diamonds can calculate the effective properties for some cross-section shapes. However, these calculations are only compatible with Eurocode.