We have a Wordpress website with 4000 subscribers and we'd like to sent an email for each one after post.
We are actually using Sendgrig as SMTP, but the problem is on our server, that slowly handle each send. Two posts can generate a queue with 8000 mails to be send, sometimes it gets stuck.
How to solve this problem? Some implementation in our side? Another third-part service?
Do you use a newsletter plugin to send out the emails? Sometimes they have a setting where you can send them in batches of X number at a time. We use https://en-gb.wordpress.org/plugins/newsletters-lite/ and it sends to the entire subscriber list but you set the interval (we use 120 seconds) and the batch size (20, 50 etc) & then it emails us when it's complete, although you'd need to pro version with the amount of subscribers you have.