My permohonan lulus 2 days ago.
Yesterday check, Tidak Lulus reason being Duplikasi Permohonan.
Is it because i registered my wife for BPN, that the system detected as duplicate?
What to do? should i do Rayuan or what?

Duplikasi? How is that possible?
You applied twice?

Maybe their LHDN 2018, above RM4001?
Are you married? If that's the case, check your spouse BPN status.

Otherwise, you can go BSN to claim the BPN money with that LULUS email.
Actually if parent mean household or married couple, only eligible for RM1000 or RM1600.
Only one of them to apply as Married. Of course need to fill in their spouse information as well.
Link to apply BPN:
https://bpn.hasil.gov.my/PermohonanPage2020.aspx
As long as your LULUS email and BPN status is LULUS, you just wait for BPN payment. Last year tax / e-filing, the bank still active? Then, it should be fine for you.
Otherwise, can go to BSN and claim back your BPN money.

Bantuan Prihatin Nasional (BPN) Payment on:
B40 Single & Household RM0 ~ RM4000 = 6 ~ 12 April 2020
M40 Household RM4001 ~ RM8000 = 13 ~ 15 April 2020