LLP - DPIN ofNominee for Body Corporate not accepted to be added as a partner

In the case of an LLP, there are three partners, one is  and LLP all are Designated Partners. Someone- say ‘Mr A’ is  a nominee, and also a DP. Another partner is also a DP.    Now Mr A is also going to become a partner. When I am filing Form 4 for adding him as a partner and filling DPIN, it asks for a unique DPIN. In such a case where I have only 1 individual and 1 body corporate as partners and but a third person Mr A who is a nominee of the LLP, but has to be added  as a third partner, how can I proceed with the filing as DPIN is not being accepted. Please help.