With the release of MySQL 8.0.32, the permissions required to perform a database backup have changed. Database users performing the back up are now required to have the FLUSH_TABLES privilege.

The OPC will attempt to automatically grant this permission to your existing database user, but if this is unsuccessful, you will need to grant this permission manually with the following command:

GRANT FLUSH_TABLES ON *.* TO 'user'@'host';
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(You will need to replace 'user'@'host' with the username and host of your database user)

This will then allow the OPC to continue to perform database backups.