ORA-16479: cannot connect to the far sync instance
Cause:
An attempt was made to connect to the far sync instance to help facilitate the failover operation but the connection attempt failed.
Action:
Make sure the far sync instance is mounted. Check the alert log and trace files on both the current database and the far sync instance for further details. Retry the operation if a problem is identified and corrected. Using the FORCE option on the failover command allows the operation to proceed and bypass the far sync instance but bypassing the far sync instance increases the potential for data loss.