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.
Sending that many emails directly from your WordPress server is usually not a great idea - most hosting packages are not prepared for that and you could run into different issues; except the slowness, you could potentially get your domain marked as spam.
If you are on a shared hosting plan, other people could create bad reputation for the email server you are sharing so that's another reason why you should avoid sending mass emails like that - plus, you also risk of doing the same for other people's websites as well.
Definitely go with a 3rd party service, maybe MailChimp or something similar, it won't be difficult to research which would best fit your needs and budget.
