We keep getting an error code on PostgresSQL while using the Query Editor.

https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/query-editor.html#query-editor.regions

Make sure your User/Role has enough permissions

The following policy provides the minimum required permissions for a user to access the query editor.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "QueryEditor0",
            "Effect": "Allow",
            "Action": [
                "secretsmanager:GetSecretValue",
                "secretsmanager:PutResourcePolicy",
                "secretsmanager:PutSecretValue",
                "secretsmanager:DeleteSecret",
                "secretsmanager:DescribeSecret",
                "secretsmanager:TagResource"
            ],
            "Resource": "arn:aws:secretsmanager:*:*:secret:rds-db-credentials/*"
        },
        {
            "Sid": "QueryEditor1",
            "Effect": "Allow",
            "Action": [
                "secretsmanager:GetRandomPassword",
                "tag:GetResources",
                "secretsmanager:CreateSecret",
                "secretsmanager:ListSecrets",
                "dbqms:CreateFavoriteQuery",
                "dbqms:DescribeFavoriteQueries",
                "dbqms:UpdateFavoriteQuery",
                "dbqms:DeleteFavoriteQueries",
                "dbqms:GetQueryString",
                "dbqms:CreateQueryHistory",
                "dbqms:UpdateQueryHistory",
                "dbqms:DeleteQueryHistory",
                "dbqms:DescribeQueryHistory",
                "rds-data:BatchExecuteStatement",
                "rds-data:BeginTransaction",
                "rds-data:CommitTransaction",
                "rds-data:ExecuteStatement",
                "rds-data:RollbackTransaction"
            ],
            "Resource": "*"
        }
    ]
}