How to resolve "valid signing identity not found" in provisioning profiles library

When creating certificate via KeyChain in an old mac, then you want to use it in a new mac, you may see the following warning "valid signing identity not found" inprovisioning profiles library. How to resolve it? two solutions:

1. Transferring you identity from old mac to the new mac.
   • Export from old mac
     • In the Xcode Organizer, select your team in the Teams section.
     • Click Export.
     • Specify a filename and a password, and click Save.
   • Import to new mac
     • In the Xcode Organizer, select your team in the Teams section.
     • Click Import.
     • Select the file containing your code signing assets.
     • Enter the password for the file, and click Open.
2. Create a new certificate via keychain in your new mac and upload to apple website.