After upgrading from Splunk 6.2.3 to 6.3.0, why am I getting renew-certs startup error "not a renewed Splunk certificate: aborting renewal"?

Hi, I was doing an upgrade from Splunk 6.2.3 to 6.3.0. Installation went fine, but when I start Splunk for the first time, I'm getting the error below: ERROR: "/opt/splunk/etc/auth/ca.pem.default": not a renewed Splunk certificate: aborting renewal ERROR while running renew-certs migration. Thanks!