LTBeamN 'sections are not compatible'

[rather_be_riding]

I'm trying to do an LTBeamN buckling check of a stacked column arrangement and I've got this error. Does anyone know what it means - I can't make head nor tail of the French manual to try and sort it out. Sections are property specified:

h: 280
A: 5726.2
Iy: 3.78E+7
Iz: 3.78E+7
It: 3.784E+7
Iw: 2.43E+11

h: 400
A: 8606.1
Iy: 7.991E+7
Iz: 7.991E+7
It: 3.797E+7
Iw: 6.985E+11

Also is anyone aware of a way that you can achieve a section change at say a flange style connection rather than tapering?

 

[271828]

What software?

 

[rather_be_riding]

LTBeamN per the title and first line of the post.

 

[Agent666]

You can convert the manual to an English pdf online. Not come across that error before though. Just search for pdf translator.

https://engineervsheep.com

 

[rather_be_riding]

Agent666 - yes I'm aware and had already done so but it doesn't seem to offer much explanation for this issue either. Of course that could possibly be not helped by the translation but I've struggled to see anything that looks applicable really.