How many emails was send per minute?
Mails was sended via MailJet API, but I using cron to provide data to MailJet. Earlier plugin broken down via php max_execution_time. So I decided to use cron. Cron is sending 25 mails per minute, so 36 000 per day. You can change this value.
Edit line 17 in ow_plugins/mailjet/bol/service.php
const MAILS_ARRAY_MAX_RECORDS = 25;
Attention: If you set big value, then script can broke down. You must then change max_execution_time in your php.ini file
------------------
How can i check if mails was sended?
You have log tab on plugin settings page. This will display if emails was sended (you can check emaillist) or occured errors