On July 10, 2017, the Intel XDK cloud-based build servers were retired. You can no longer build a Cordova mobile app directly using the Intel XDK, with any version of the Intel XDK. You can build your mobile app using either PhoneGap Build or Cordova CLI.
As mentioned by Ashley in a March post :
We knew this was coming in advance and it was one of the factors in creating our own build service. We're also going to look in to using the C3 build service to build exports from C2 so you can use that as a replacement without having to import your project (which could be tricky if you don't have all third-party addons for C3). Also you can, as ever, still use PhoneGap Build, so nobody's left out in the cold. We're also going to look in to making it easier to use the Cordova CLI for local builds. And you still have a few months to use the Intel XDK.
I don't use C3 but you can inquire in that section of the forums about the build export capabilities.