Answer:
Check the cross-sections of your frame joint or connection.
The program checks whether the assignment of members is allowed for the calculation. If this is not the case, a footnote is displayed, which is explained in the "Comment" column. You have probably used a cross-section that is not intended for the connection design.
In our example, Note 23 is displayed and then the left beam is assigned manually: "Left Beam: Cross-section is not an I-section."
In Window 1.2 Cross-Sections, you can open the cross-section library to check which cross-sections can be selected for the frame joint type (activate the manual definition of geometry in Window 1.1 "General Data").
