When you send mass emails, the SMTP server puts them automatically into an email queue with other messages: the delivery starts from the first ones and then carries on with the others. But some ISPs may enforce rate limits on IP addresses according to their trust level and reputation; so if too many messages (or a certain amount of very heavy emails) are transiting, the IP can delay the delivery. The email queue doesn’t move anymore, and the traffic is congested – just like with acar queue
turboSMTP’s dashboard shows it with a handy chart, giving you both the queued mail rate and the state of any single message:
turboSMTP’s professional service tries to send again the queued email contacting the incoming server, more times than a normal SMTP would do. This way the queue is pushed to move quicker than usual, and it’s easily solved.
Also, turboSMTP offers you the upgrade to a monitored, dedicated IP: in place of sharing it with other users (thus diminishing its delivery capacity), you can have it all your own and maximize the speed of your email flow.
Remember that a queued email is not a bounce (the messages will be sent anyway), but it can be a very annoying issue if you planned to deliver a newsletter at a right time of the day.