Oracle Error Message
ORA-16724: cannot resolve gap for one or more standby databases
Reason for the Error
The primary database could not resolve a gap request from one or more standby databases.
Solution
To see which standby database has an unresolvable gap, check the status of the primary database using either Enterprise Manager or the DGMGRL CLI SHOW DATABASE command. Copy the missing archived log files from either backups or from another database in the configuration that has the files to the standby database that is missing the files.