I have a valid link but the external link checker has a invalid status.
One of the possibilities explained at [2]. Also note Link checker schedulded to run at configured value[1], Make sure to reverify approprately.
[1] http://<host>:<port>/system/console/configMgr/com.day.cq.rewriter.linkchecker .impl.LinkCheckerTask
North America
Europe, Middle East and Africa
Asia Pacific