sending mail cron job not running automatically

I seem to have an issue with the sending mail cron job. Its not working :-(

If i run it manually it works fine so i know all the server settings are correct. Mailwizz is running on a dedicated Ubuntu servers at AWS, i have complete control and SSH access. If i run the cron command manually via SHH its fine but it only processes 100 messages and i have to run it again which i beleive is correct.

I'm not sure if the /etc/crontab file manages all cron jobs for mailwizz but if it does the 1 min send mail job isn't listed.

Can anyone suggest where the job needs to be added to automate it as it should be.