If your company is sending hundreds of thousands of emails per delivery, you can run into some significant issues with internet service providers routing all of your emails into the junk folder. ESPs often guarantee that they send an email and often talk about their high delivery rates, but that actually includes delivering an email into a junk folder. In order to actually see your inbox deliverability, you have to utilize a third-party platform like our partners at 250ok.
Every server that sends email has an IP address associated with it, and ISPs maintain directories of these IP addresses and how many bounce and spam complaints they receive from their users on the email sent from those IP addresses. It's not uncommon for some ISPs to get a few complaints and immediately route all further emails to the junk folder instead of the inbox.
Migrating to a New Email Service Provider
While your subscriber list can be 100% legitimate email subscribers who opted in, or double opted in, to your marketing emails… migrating to a new email service provider and sending to your entire list can spell doom. A few complaints can instantly get your IP address flagged and no one will receive your email in their inbox.
As a best practice, when large senders are migrating to a new email service provider, it's recommended that the IP address be warmed up. That is, you maintain your existing email service provider while increasing the number of messages you send through the new service… until you build a reputation for that new IP address. Over time, you can migrate all of your messaging but you never want to do it at one time.
Email Marketing: What is IP Warming?
Just like a warm up consists of a gradual increase in the intensity of physical activity to warm the muscles and reduce the risk of injury, IP warming is the process of systematic addition of campaign volume every week in the new IP address. Doing so will help in establishing a positive sending reputation with Internet Service Providers (ISPs).
IP Warming Infographic
This infographic from Uplers defines and illustrates best practices for warming up your IP address with your new email service provider, walking you through 5 key steps:
- Make sure you follow all the email deliverability best practices before sending the first lot of emails for IP warming.
- Your dedicated IP should have a pointer record set up in your reverse DNS (Domain Name System).
- Segment the email subscribers based on their engagement with your previous emails.
- The key to successful IP warming is gradually increasing the number of emails you send.
- Carry out the post-send hygiene.
They also point out some exceptions with specific Internet Service Providers (ISPS):
- Yahoo, AOL, and Gmail present some bulking issues by dividing emails into discrete bulks, thereby delaying the email delivery. It will get resolved once you send some emails with positive metrics.
- Delays are normal at AOL, Microsoft, and Comcast. These delays or 421 bounces will retry for 72 hours. If it cannot be delivered after that time, they will bounce as a 5XX and the bounce record will be saved as 421 error. Once your reputation develops, there won’t be any further delays.