Clarity typically sends an OCI0000064 email alert when the security server is unable to communicate with the database. Follow these steps to get them talking again.
OCI0000064 alerts are generated when the security server is started before the database. The database should always be restarted before any other JDE server.
To resolve this error, first restart the database. Then, wait for database services to fully start before moving on to the security server or html servers.