I have this pretty often: working links get marked as broken. I visit the page myself and check the headers and they are ok.
Here are two samples:
Link last checked : 20.08.2013 HTTP code : 403 Response time : 0.355 seconds Final URL : http://opendesignct.com/events/wdc-2014-show-and-tell/ Redirect count : 0 Instance count : 1 This link has failed 1 time. This link has been broken for 12 minutes. Log : === HTTP code : 403 === HTTP/1.1 403 Forbidden Date: Tue, 20 Aug 2013 08:27:47 GMT Server: Apache Accept-Ranges: bytes Content-Length: 159 Connection: close Content-Type: text/html Link is broken.
Link last checked : 20.08.2013 HTTP code : 999 Response time : 0.077 seconds Final URL : http://www.linkedin.com/pub/alexandra-seiler/55/583/495 Redirect count : 0 Instance count : 1 This link has failed 1 time. This link has been broken for 1 minute. Log : === HTTP code : 999 === HTTP/1.1 999 INKApi Error Date: Tue, 20 Aug 2013 08:39:18 GMT nnCoection: close Server: ATS X-Li-Pop: PROD-IDB2 Content-Length: 511 Content-Type: text/html Set-Cookie: X-LI-IDC=C4 Link is broken.
Any idea what could be wrong here? If I visit both sites, I get: Status: HTTP/1.1 200 OK