Add tel: to the Link Checker Special Link Prefixes http://localhost:4502/system/console/configMgr/com.day.cq.rewriter.linkchecker.impl.LinkCheckerImplor Add condition to overriden rewriteLink method to return link in case value starts with tel:
GO to this url https://oakutils.appspot.com/generate/index paste query and generate index definition, copy xml format and add to oak:index/.content.xml and update filter.xml to deploy