16816, 0000, "incorrect database role"
*Cause: The Data Guard broker detected that the specified database
had a different database role than that recorded in the 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 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 Data Guard