ORA-00260: cannot find online log sequence string for thread string
Cause: The log sequence number supplied to the archival command does not match any of the online logs for the thread. The log might have been reused for another sequence number, it might have been dropped, the sequence number might be greater than the current log sequence number, or the thread might not have any logs.
Action: Check the ARCHIVE statement, then specify a valid log sequence number. Specify a valid log sequence number.
