ORA-16161: Cannot mix standby and online redo log file members for group string
Cause: An attempt was made to add a log file member that does not match the other member types. This problem typically occurs when adding a standby log file member to an online redo logfile group, or adding an online redo log file member to a standby redo log file group.
Action: Verify the log file group type using the TYPE column of the V$LOG fixed view.