If you cannot store the certificate in the System keychain, create it in the login keychain, then exported it. You can then import it into the System keychain.
Using the contextual menu for the certificate, select Get Info, open the Trust item, and set Code Signing to Always Trust.
Finally, quit Keychain Access application to refresh the certificate store.
The official said so,
You first set to log on, and then imported into the system.
Follow the steps first, continues (to log in).
Select Export:
Export.
Select File >> Import Project:
Select the certificate and click Open.
Finally, is this the same again.
