Element 'crontab': This element is not expected.

[rikwillems]

File Product/etc/config.xml has an error that is produced in setup upgrade and accessing the backend configuration: Element 'crontab': This element is not expected.

This is the invalid code:

    <crontab>
        <default>
            <jobs>
                <ac_product_sync_cron_job>
                    <schedule>
                        <cron_expr>*/10 * * * *</cron_expr>
                    </schedule>
                    <run>
                        <model>ActiveCampaign\Product\Cron\ProductSyncCron::execute</model>
                    </run>
                </ac_product_sync_cron_job>
            </jobs>
        </default>
    </crontab>