This morning I noticed a high Google traffic page of mine had completely disappeared from the SERP's. Google Webmaster Tools reports a HTTP error: "domain name not found" for about 400 pages with this particular page being in the list.
However, all the other pages on this list that I checked are still in the index.
Could this be the cause of it disappearing or could it be something else?
Will submitting a Sitemap help it reappear quicker?
Just to clarify, Webmaster Tools is never a cause - it's a report for the webmaster, often helpful and sometimes buggy. That particular report sounds like there was either a DNS problem or a server problem when Google tried to spider. Is that a possibility?
Very possible. Yes, traffic was way down on that day.
I think I can see what has happened. I have another thumbnail page, down a level, which is almost identical (only to robots) to the page that disappeared. The page not being available for spidering may have triggered Google to display this one in the index instead. Trouble is, it doesn't rank as good as there are no backlinks to it. Could a 301 redirect here bring this page back in a timely fashion?