Mail Queue Management
A list of the email notifications that are queued and ready to be sent in batches. The ‘Process Emails’ button allows the administrator to send a batch of emails immediately, regardless of the status of the queue.
External cron job
You can use an external Cron Job, like a one that cpanel has to offer. To use it head to PeepSo Config > Advanced Options and disable PeepSo Default Mailqueue like it's shown in the screenshot below:
For more help with setting up cron jobs you can also contact your hosting provider for more information on how to get it setup in your particular environment. There's also a great video tutorial that's available here explaining what a cron job is and how it works.
The command that you should use is:
where in place of 'domain.com' you should enter your own domain name.
Setting the cron to run every 5 minutes works best for most sites.