If you are using M2E Pro version 6.1.1 or higher for Magento v 1.x and all M2E Pro versions for Magento v 2.x, no particular settings for automatic synchronization are required. However, if automatic synchronization is not working properly, please contact M2E Pro support.
If you are using M2E Pro version 6.1.0 or lower for Magento v 1.x or you want to set Magento Cron additionally, please follow the instructions below.
Command PHP: php -q /%PATH_MAGENTO_ROOT_CATALOG%/cron.php -mdefault 1
Command GET: GET http://%YOUR_DOMAIN%/cron.php
crontab -u -e
* * * * * /bin/magento cron:run
It is strongly recommended to set up Cron to run every 1 minute (e.g. * * * * *). Please check this post (true for all versions).
If the automatic synchronization is still not performed, read the article for the details on how to resolve the problem.
To learn why the automatic synchronization is required, you can review this article.