Mailchimp email sending isvery reliable and all your email messages will get sent. Why the message may not reach your recipients is up to several factors including:
- The receiving server identifying the incoming message as spam.
- Your sending email address or server being on a known spam/junk sender list.
- The receiving server is unavailable for some permanent or temporary reason.
- The recipients email address has been entered incorrectly (e.g. email@example.com instead of firstname.lastname@example.org).
- The recipient isn’t receiving messages (e.g. a full inbox).
There are several things that can be done to improve the chance of your emails reaching intended recipients such as configuring SPF and DKIM records where possible (you should do this for your Mailchimp account ) and ensuring that your messages don’t appear ‘spammy’ to receiving servers.
Last Friday Mailchimp sent 1.5 billion email messages with the average receipt time by subscribers being one minute (i.e. the email messages were received on average a minute after Mailchimp sent the email). Mailchimp is very good at sending massive amounts of messages in very short spaces of time. Receiving servers however aren’t always as good at delivering messages to intended recipients.