Cant export a part

First of all - best AI tool so far. Im very intested in long term usage.

After work with AI i got perfect results but I cant export them to STL.

Here is recoreded video with problem: https://zawojit.fra1.cdn.digitaloceanspaces.com/z4prints-website/Nagranie%20z%20ekranu%202026-03-13%20o%2022.45.53.mov

But in words. I try to export and get these wierd error: