The Web server (running the Web site) thinks that the URL requested by the client (e.g. your Web browser or our CheckUpDown robot) is no longer available from that system. This is not a 'never heard of it' response, but a 'does not live here any more' response.
The 410 error also indicates that the Web server has no forwarding address for the URL, so can provide no redirection to the new Web server. This condition should generally be considered permanent. If the Web server does not know, or has no way of knowing, whether or not the condition is permanent, the status code 404 - Not found should be used instead.
The 410 error is primarily intended to assist the task of Web maintenance by notifying the client system that the resource is intentionally unavailable and that the Web server wants remote links to the URL to be removed. Such an event is common for URLs which are effectively dead i.e. were deliberately time-limited or simply orphaned. The Web server has complete discretion as to how long it provides the 410 error before switching to another error such as 404. (Last updated: March 2012).
The Web server does have some record of the requested URL, but now believes that this URL should be serviced by a different Web server. The 410 error indicates a complete dead-end. The URL is effectively useless, and there is no clue as to an alternative Web server or URL which might be used instead.
If the URL really should be alive, then there is something fundamentally wrong with the setup of the Web server. You should see a similar 'not found' message when you try to access the site using any Web browser. Refer this to the Webmaster of the Web site.
Our service monitors your site for HTTP errors like 410. If the URL is genuinely dead, we may have to suspend your CheckUpDown account so that we do not waste Internet resources.
Any client (e.g. your Web browser or our CheckUpDown robot) goes through the following cycle when it communicates with the Web server:
This error occurs in the final step above when the client receives an HTTP status code that it recognises as '410'.