Airbus A310-300 ILS capture loc

so i watched some videos and many players have this issue . How to active clearly the ils descent on this planes .
frequency / crs ok
Active approach on the fmc ok
Ap on , autothrust on , nav / loc or ground ? and auto land ?
Security system on this arplane or special procedural step ont his airbus ?
i see clearly the GS lock and capture but the plane refuse to active the auto descent … Why … ?

If someone have some informations. Thank you all.