Oracle® Database 11g / 12c / 18c error codes ORA-12334: database (link name [string]) is still open
ORA-12334: database (link name [string]) is still open
Oracle Error Code: ORA-12334
Cause: You attempted to dismount a database that is still open.
Action: Close the database with the ALTER DATABASE
CLOSE command, then re-attempt to dismount the database.