Unable to fix signing identity issue on Xcode

It's a propagation server issue. Wait approximately 10 minutes and it will be fixed.

For me to solve this problem I had to login to http://itunesconnect.apple.com. There was a yellow banner that kindof told me what to do. I had to go to Contracts, Tax, and Banking and setup the contracts there.

In my case the solution was:

1. Xcode: Preferences / Accounts / View Details...;
2. Click refresh (bottom left);
3. "Certificate Not Found" box pops-up with

"Your Mac Development Certificate for “your name” was not found on the Member Center. Xcode can submit a certificate signing request on your behalf. Would you like Xcode to do so now?

4. Click Request and tick all certificates in the next screen;
5. 15 sec of waiting and the issue fixed.