How to use a different root path for labelstudio

I want to serve labelstudio under a different path in stead of the root URL.

I found that I could use LABEL_STUDIO_BASE_URL=/labelstudio/

But that does not seem to work, since I am getting an error (Heidi’s down).
I see 404 error in the log as well.

How do I configure labelstudio to use a different root URL?