ORA-00362: member is required to form a valid logfile in group string

stale status of redo logs.......

ORA-00362:

member is required to form a valid logfile in group stringCause:A request to drop a logfile member was denied because it would remove data required to form a complete logfile.
Action:If desired, delete the entire log (after archiving if required), by using DROP LOGFILE;

This status means the logfile contains incomplete redo info. This status prevents the logfile from being dropped without being archived first. You should not worry about this status unless it happens repeatedly. Becuase "stale" does not mean "invalid". When this redo group becomes current, this state will automatically become valid

alter system switch logfile;

then check v$logfile again