ORA-16700: The standby database has diverged from the primary database.

 https://subhanuddinkhadri.blogspot.com/2015/10/flashback-standby-after-resetlogs-on.html

http://anuj-singh.blogspot.com/2018/06/oracle-flashback-for-standby-database.html

Error code: ORA-16700
Description: the standby database has diverged from the primary database
Cause: The primary database may have been flashed back or restored from a backup set and then reopened with the RESETLOGS option.
Action: Re-create the standby database from the primary database or flash back the standby database to the same point the primary database had been flashed back to.

The primary database may has been flashed back or restored from a backup set and then re-opened with the RESETLOGS option.

This happened because when due to an incomplete recovery in primary database, it has to be opened using resetlogs option and incarnation of primary and standby becomes different due to resetlogs option.

This error will appear in the alertlog and DGMGRL> show database  mtproddr

How to deal with ORA-16700:

Reinstantiate the standby database from the primary database.

Flashback the Standby database

We do not have to rebuild our standby, just move standby database using flashback to a previous SCN value when the incarnation of primary and standby was same. Start the MRP manually or bounce the configuration in DG broker.