Git error - gpg failed to sign data

Question

I just started using git and I install git and gpg via homebrew. For some reason, I get this error when i do git commit I looked at so many other stackoverflow

Answer 1

I had made a git key with 3 separate keys for certify / sign / encrypt & the key showed as expired in the future (after working fine for a few days):

pub   rsa4096/4CD1E9DA 2017-04-26 [C] [expired: 2017-04-28]
      Key fingerprint = 4670 59C1 7592 08B8 7FA5  313B 2A42 B6A6 4CD1 E9DA
uid         [ expired] Stuart Cardall (GIT Development Keys) 
sub   rsa4096/5195E715 2017-04-26 [E] [expired: 2019-04-26]
sub   rsa4096/DB74C297 2017-04-26 [S] [expired: 2019-04-26]
sub   rsa2048/A3913A3C 2017-04-28 [] [expired: never     ]

made a new key without adding separate subkeys to solve the problem.