Hi,
Thanks for attaching your data file.
I can't find anything wring with the section and parameters so I'm not sure why this section is not converging with the NA fixed at 90 degrees. It converges ok if it is allowed to be free. However, I found that if I rotated the section by 90 degrees and analysed with the NA fixed horizontal it also converges ok and this is exactly the same as the original analysis.
It should be noted that when the section is rotated it resolves all applied forces and moments into the new axis directions so you don't have to make any changes to the applied loading tables. However the user defined names of the load cases is not changed so the naming you have used may be a little confusing (I found it a little confusing anyway as it looks like you were using Eurocode convention for the names ie My Mz Nx Vz Vy where the loads are applied in the BS convention which are Mx My Ax Vy Vx.)
I hope this helps and I'm sorry I can't be more helpful
If this has answered your query please mark my reply as a solution so that others may benefit. Thanks
Kind regards
Dave Geeves
