ORA-16816
incorrect database role
Cause
The Oracle Data Guard broker detected that the specified database had a different database role from the one that was recorded in the Oracle Data Guard broker configuration. This could be the result of a failed switchover or failover operation, or a switchover or failover operation performed with SQL*Plus.
Action
Check the Oracle Data Guard broker documentation to see how to recover from failed role change operations, or from role changes that were performed using SQL*Plus for databases managed by Oracle Data Guard broker.