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MySQL error code

MySQL error 3857

MySQL server error 3857 is ER_RPL_CANT_STOP_REPLICA_WHILE_LOCKED_BACKUP, reported with SQLSTATE HY000.

Cannot stop the replica SQL thread while the instance is locked for backup. Try running `UNLOCK INSTANCE` first.
Error3857
NameER_RPL_CANT_STOP_REPLICA_WHILE_LOCKED_BACKUP
SQLSTATEHY000
GroupServer errors

Source: MySQL 8.4 Error Reference