Hey there,

I am really sorry for the delay of this reply as it is a weekend for us here.

I assuming you already setup cronjob for this, may i know how many cron interval you set?

And do you count how many email notification it suppose to send out to your site subscriber when a new blog post published on the site?

All of these might be related is because imagine new blog post published, so system will generate 100 pending email notification, if your cron interval set to 10 minute per time, and each of cron execute time send out 20 emails, so it need around 50minute in order to send out these pending emails to your site subscriber.

What i suggest is :
1. set your cron interval to 5 minute
2. If your server performance can maintenance send out a lot of email in the short time, you can set this 'Process how many emails at a time' to 50 ~ 100, you can check my attached screenshot below which setting i referring to.

OK, thanks. The cron is set up for 5 min intervals. They have about 1,000 subscribers. I guess we could try sending out more emails at a time? Not sure if we can control that and if so, sending out too many will cause spam issues?

Hey,

It actually depends on your hosting provider. Some hosting providers has a threshold of e-mail sending of 200 - 500 within an hour until it sends the admin of the server a warning that there could be an ongoing spam. It really depends on your host.

If you could set it up at about 2 - 3 minutes for the cronjob, it should be able to do well with 1000 - 2000 subscribers but it also depends on how many posts you are doing.