Over the past 4 months, since redesigning our site, our main product pages have not been indexed. About 3 weeks ago, Google Webmaster Tools started to report that the pages returned a 404 (not found) status.
Going directly onto the pages or clicking through to them from links creates no problems and the pages load up fine with no 404 errors. We have looked at everything we can think of to try to work out why the pages are returning this error but have not been able to find anything.
Well, then you know the problem is on your end and not Google’s. Fix your website so that it sends the correct status code (200) when serving a webpage that exists.
Clicked on your url, in Firefox your site loaded rapidly without the 404. Everything looks fine, pages are working. I repeated twice that, it looks good from here.
Have double checked the HTTP status code through an external checker and it is the same as webmaster tools - 404 not found
I have checked going directly to the page after clearing the cache and from a computer that has never accessed the website before and the page shows up fine
What is the site? (You can type it in as text, i.e. example.com, without creating a link)
Have you checked what HTTP status code is being returned when these pages are accessed? Just because you can view the content does not mean the wrong status header wasn’t sent.
Have you checked that you can access these pages of your site in a fresh browser with cleared cookies without first visiting any other page of your site? This is how Google accesses it, so if visiting your home page to set some cookies is a prerequisite to accessing these pages, it won’t be able to.
A server sending the wrong HTTP response code is not a DNS issue. A 404 response means the domain was resolved, a connection to the server established and the HTTP request received and responded to. Far past the point of DNS in the chain of events.