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Email Campaigns

Email Delivery Speeds

Maxmail slows down campaigns

There are several reasons for a campaign to be sent slow.

Sending speeds are dependent on several factors such as the quality of your mailing list, the content of your campaign and the location from which you are connecting to Maxmail.

The number one reason for campaign delivery to be slow is a large number of Yahoo and Hotmail email addresses in your mailing list. All major ISPs like Yahoo, MSN, Hotmail and Gmail have restrictions on the number of concurrent emails that can be delivered to their network at any given time. If there are too many connections or emails trying to reach a Yahoo inbox (say) chances are Yahoo will start "deferring" your emails.

Deferring does not mean "non-delivery", however does put a great deal of load on our sending servers. These deferred emails are going to be re-tried in the background "x" number of times to try delivering the email. After a certain number of attempts if Yahoo still responds with a "deferred" status then Maxmail will consider that to be a "hard bounce" and quit trying.

However, in recent days we've introduced two very critical feature updates that makes email sending that much more effective.

Domain Level Throttling

When emails are being sent, Maxmail automatically determines the optimum rate at which emails can be delivered to a particular domain (e.g., or Then as emails are "departing" the Maxmail sending servers, this rate limits the maximum number of emails that will be delivered to a particular domain in a minute. This rate ranges from 60 to 1000 depending on which domain you are sending to.

Predictive Bounce-Back Handler

This technology attempts to predict the SMTP response codes that an email address will generate if and when an email is sent to the address. For instance if you have a subscriber, Maxmail will do a background check to see whether the address is going to generate an "OK" response when an email is sent.There are a number of possible responses that can be generated and Maxmail has a way of appropriately handling each one of them. This way, when you send a campaign, you are

1. Sending the campaign to addresses that have a near 100% chance of receiving it

2. By-passing the "deferred" scenario that would normally slow things down for you.

Read more about the Predictive Bounce-Back Handler

Currently Maxmail is delivering emails up to 1,500 per minute depending on the quality of your list, your location and also the content of your campaigns.

One way to enhance your sending speeds is by opting for our Enterprise Unlimited Plan where you get a deicated sending trunk of your own with DKIM, Sub-Domain, SPF and PTR enabled sending for increased delivery rates. Its the best option for our high-volume senders and offers the greatest value.

NOTE: For customers that have a real need for speedy inbox delivery, we have the Enterprise Unlimited Email Marketing plan that gives you a dedicated delivery network and a whole bunch of other benefits that dramatically increase the speed and delivery of your campaigns.

Need more help?

NZ Toll Free: 0800 121 131

International: (64) 9 309 8288

Australia: (61) 2 9098 8405

Canada: (1) 604 259 1329

United Kingdom: (44) 20 3670 2364

United States: (1) 929 229 4855