This will fix the issue on Bing for users, but Bing must have found this URL somehow, so presumably there is a link somewhere to the non www and the link is powerful enough to get bing confused, so another reason for the 301.
Thanks for that, Receptional. I'll do the 301. What's odd is that 3 (out of 10) of the entries on the same results page suffer the same fate. I'm pretty certain that there are no incorrectly written links on my site or in my sitemap that could be misleading Bing. Curious.
you should always provide a 301 redirect to the canonical domain.
you should also consider a few other possible problems: - make sure the indexed non-canonical url doesn't also have additional misspelling, missing or wrong punctuation, etc that could be causing the "not found" error.
- check that your custom "not found" page is returning a HTTP 404 response rather than a 200 OK.