I got this error the other day:
```
Code Sign error: The identity 'iPhone Developer' doesn't match any valid certificate/private key pair in the default keychain
```
The fix for me was this:
- Login to iPhone Developer Program
- Click on Certificates
- Under Current Development Certificates click on the button to download your certificate. It gets saved as developer\_identity.cer.
- Open the Keychain tool
- Make sure the "login" keychain is selected in the left pane.
- Make sure that "login" is the default keychain (right-click on the login item to do this)
- Drag the developer\_identity.cer file to the login keychain's list of certificates.
- Build your app