What does it mean?
Rust or corrosion may affect parts of the vehicle’s structure. How serious it is depends on the location, size and whether load-bearing structure is weakened.
What should I ask a workshop?
Ask a qualified workshop to inspect the affected area and evaluate the feasible repair work.
Safety note
Structural corrosion can be serious. Never infer roadworthiness from this general explanation.
What about re-inspection?
In Finland, re-inspection is generally required within one month of a failed inspection if you want the defects reviewed without repeating the entire inspection. This does not establish driving permission. Check the actual decision and current official requirements.