This is the same exact error for an expired Apple cert – though I know it’s not your issue, you’re the #1 answer on Bing at the moment.
According to the Apple Developer Forums, the Apple Worldwide Developer Relations Intermediate Certificate Expiration expired 2/14/2016.
… This issue stems from having a copy of the expired WWDR Intermediate certificate in both your System and Login keychains. To resolve the issue, you should first download and install the new WWDR intermediate certificate (by double-clicking on the file). Next, in the Keychain Access application, select the System keychain. Make sure to select “Show Expired Certificates” in the View menu and then delete the expired version of the Apple Worldwide Developer Relations Certificate Authority Intermediate certificate (expired on February 14, 2016). Your certificates should now appear as valid in Keychain Access and be available to Xcode for submissions to the App Store.
You can get a new cert (which expires February 7, 2023). The AppleWWDRCA.cer is available on the explanation page: https://developer.apple.com/support/certificates/expiration/
BTW: it appears this new cert is installed with Xcode 7.2.1