ORA-00390: log [string] of thread [string] is being cleared, cannot become current log
Cause: An attempt to switch to a new online log for the redo thread failed because no reusable log could be found. This log is being cleared and will be useable when the clearing completes. The command that began the clearing may have terminated without completing the clearing.
Action: If the clear command is still executing then wait for its completion. If it terminated then reissue the clear command, or drop the log.