Hi @Xdrakosha
My understanding is the red color indicates that the geometry exceeds certains limits’ especially curvature limit. This happens when fillets are wider than the face they are rounding, or if you twist a body too much.
Please have a look at this post Inserted Step file - #2 by PEC
On way to find the root cause is to insert breakpoint in the history to redo step by step the creation of the body, identify the step involved, and then edit the operation’s parameters until the red color disappears.
Hope it helps.
Pec