Bing hasn't indexed my site for 6 months or so now, which means that DuckDuckGo doesn't show results from my site either. From what I've been able to tell, there's absolutely no way to fix it short of a response from Microsoft (there's certainly not enough information to figure it out from their web developer tools) - of course I never received a response. Google, for all their faults, at least works. DDG need to fix their data sourcing because Bing really is the worst search engine...