Answer
(Fatwa: 487/487/M=1431)
Walimah is sunnah after nikah or rukhsati. If only your engagement was announced i.e. only the proposal of nikah was finalised, and formal nikah (with ijab and qubool) was not carried out, in this case there is no need to perform walimah. And if your nikah was performed but there was no rukhsati then hold walimah after rukhsati (meeting the spouse). And if nikah and rukhsati both were carried out and you could not hold walimah on time, then you missed the sunnah. There is no makeup of it after the due time of walimah passed; hence you should ask Almighty Allah for forgiveness.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband