Oracle Error Codes

log string of thread string is being cleared, cannot become current log

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.

How to Solve :

If the clear command is still executing then wait for its completion. If it terminated then reissue the clear command, or drop the log.