Possible Cause

Discovery and auto-discovery depends on the AP_SYSTEM_VOLUME license feature.

For example, if the licence is expiring on 9/15/2011 and five domains are pointing to the license server, even after expiry, the five domains will continue to work till 9/15/2012. However if we start a new domain server after 9/15/2011 that is pointing to the same license file, it will not work.