I have a Skill which links Salesforce to an Amazon Echo for case control: http://joshbirk.herokuapp.com/sf1-how-to-setup-amazon-echo-case-control-for-salesforce/
For me, it works fine. I've even demo'd earlier versions live in the past. However another developer is trying to set up a version for himself. He is working off the exact same codebase, just on another Heroku instance.
This is using Auth Code Grant. One of the Heroku endpoints serves as a middle man to hand the refresh token back to Amazon on request. In my version, the OAuth loop completes and the token endpoint gets hit. I see the "Your Skill has been Successfully Linked" message.
He completes the OAuth loop, and then the token endpoint never gets called and he sees the "Unable to Link Skill, Try Again Later".
I've checked his configuration and I don't see anything wrong/notably different from my own. I can even use his endpoint instead of my own in my ASK config and it works fine. He has Auth Code checked, the domains set, etc.
I can't find anywhere in the Amazon Developer Dashboard to get more information on *why* Amazon is unable to link this skill. An actual error would be incredibly helpful.
Any way we can dig into this deeper? We're pretty stumped here.