I am using external link check and have deliberately entered some bad external URL links to verify as part of testing that the external link checker is functioning as stated.
This is a copy of the status I am receiving from the external link checker. My question is why are 503s recorded as having valid status. I am on cq5.6
503 indicates service unavailable. Do you have proxy settings for internet connection? Or Your instance had some issue at that point of time. Check logs to see what was happening at that point of time.