Hi @goldenfish125,
In fact, there is two way to automatically trigger SMTP Mailing Queue sending :
Solution 1 : You can rely on wp_cron logic to run every “wp_cron_interval” (from advanced configuration). Important note : wp_cron only run when someone (ex : visitor) load pages. So, if you have very few visitors on your website, it could be better to choose second solution or to trigger wp-cron yourself periodically.
Solution 2 : You can rely on your own HTTP scheduler (like https://www.setcronjob.com/ or others) to call a specific URL dedicated to SMTP Mailing Queue in order to run the process.
When “Don’t use wp_cron” is checked (your case) it means that second solution have been chosen. The url to call is the one given below the description of the option.
In your case : https://www.quynhanmobile.com?smqProcessQueue&key=XXXXXX
(Note : I recommend to generate a new secret key as you hide it from the input field but it is still visible in the description of this option, oops…)
If you have a very large number of visitors, just uncheck the “Don’t use wp_cron” option and you should be done.
On my website, I oftenly do a cross solution where I disable auto execution of wp_cron job on page load define('DISABLE_WP_CRON', 'true');
then I use a provider like setCronJob or any other to call the wp-cron (https://www.example.com/wp-cron.php?doing_wp_cron).
Yours faithfully,
Birmania