Welcome 
Are you aware that you put a 5x5 rank-1 matrix as the first argument into your function FOCs?
[t t t t t] where t = ss_vec does give you just that. If that’s what you actually meant, I think the answer depends on the actual definition of FOCs
(note that a minimal working example that can be copy-pasted would make it a lot easier for people to help you. Please look also here for some other recommendations: Please read: make it easier to help you)