Yes, it is a signing issue. Have you confirmed that you are providing a mobile provisioning file that will work with your cert? Here are the lines of interest from your detailed build log:
Signing Identity: "iPhone Distribution: Paige Sullivan (4BD3RN2RPK)" Provisioning Profile: "DiaryCards distribution" (6573f3a4-95b9-4bd0-b09c-cb0e8e245a04) /usr/bin/codesign --force --sign 7942FF44B51ADCCCF5B1B99ECC187D73E3592B3A --entitlements .../app/platforms/ios/build/DiaryCards.build/Release-iphoneos/DiaryCards.build/DiaryCards.app.xcent --timestamp=none .../app/platforms/ios/build/device/DiaryCards.app 7942FF44B51ADCCCF5B1B99ECC187D73E3592B3A: no identity found Command /usr/bin/codesign failed with exit code 1 ** BUILD FAILED ** The following build commands failed: CodeSign build/device/DiaryCards.app (1 failure)
You may have to go to your Apple Dev Account and generate a new set of certs. You do not need to use the XDK to create the P12, even if you do not have a Mac, you can use a Windows machine. I've found that generating your own P12 is more reliable. See this FAQ > https://software.intel.com/en-us/xdk/faqs/general#windows-p12 < for a couple of very useful articles on how to do that.