Dormers on Roof Problem

[G.warner]

Hi i am new to this software. I am "attempting" to draft a plan for a new build development I have planning consent for.

However every time i add a floating dormer or non floating dormer i seem to have an error with the dormer roof meeting the main roof plane. I have treid starting a basic plan with a simple house with four walls and a basic hipped roof but the problem still remains.

I have followed the basic training videos, however im still getting the problem.

Has anyone come across this? or does anyone know what im doing wrong?

here is an image of my roof with the problem