How to Send an Email Blast for Lead Generation

An email blast is a cost effective way to generate leads and drive sales. Send bulk email communications to a targeted audience to boost engagement, brand awareness and customer loyalty.

So you’ve purchased a targeted b2b email list and you’re ready to send an email blast to millions of inboxes. If only it were that easy. ISPs are very protective of their customers and careful when it comes to cold email blasts sent from new IPs. New IPs equal no sender score, and since ISPs have no record of you emailing the recipients on your list, they are reluctant to deliver bulk email to their inboxes. Most ISPs set limitations on how many emails can be delivered per day until a sending reputation is established.

IP Warm-Up and Why its Important 

To send a  successful  email blast at scale to non-permission based b2b email lists, you have to warm up your IP addresses. Begin the IP warm-up process by sending email volume slowly and consistently over a period of time so you can begin to build a sender reputation with Internet Service Providers. Sending large email blasts too quickly from a new IP is a sure sign of a “spammer”, and your IPs will be blocked quickly.

The million-dollar question is how long will this IP warm-up process take before you can send an email blast at scale. Unfortunately, there is no silver bullet solution to this question. The IP warm-up process can take anywhere from 4 to 8 weeks and maybe longer for consumer emails like Gmail, Yahoo, Hotmail, etc. Factors that affect the IP warm-up period include but are not limited to: 

  1. Engagement 
  2. Hard Bounces 
  3. Blacklisted IPs by Spam Trappers
  4. Spam Complaints
  5. Email Frequency
  6. SPF and DKIM Configurations 
  7. Proper Email Formatting

Procuring a quality email list is extremely important when conducting email blasts. It is the foundation of a successful b2b email marketing campaign is built on and can make or break your marketing efforts. Clean your list to remove spam trappers, honey pots and invalid emails before beginning the warm-up process. Keep in mind that despite having a clean list you will still face deliverability issues because the recipients did not opt-in to receive communications from you. Make sure,

  1. DNS, SPF, and DKIM are properly configured
  2. Your IPs are registered with all available ISP feedback loops
  3. Your email content is CAM-SPAM compliant 

Start the warm-up process with your best email subject lines and content. Send small email blasts frequently and keep volumes consistent. Start with a few thousand addresses across all ISPs and double your volume every 3 to 4 days. 

Some of your email blasts will inbox while others will land in SPAM folders. ISPs want to see if your recipients are marking you “not SPAM” because this is an indication that they want to receive your messages. When your messages do land in the inbox, are recipients clicking on them? Are they clicking through to your landing page? Positive actions like adding your email address to the contact list, enabling images and read rate help build a positive sender reputation with ISPs.

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What to expect from your email blast

During the warm-up process, your IPs and domain may be blacklisted and outreach to inbox providers and spam trappers may be necessary to regain good standing. Your bounce rate and click rates will fluctuate if you are blacklisted. Situations may occur where you are having success to a portion of your list but as you add more addresses, deliverability issues occur. This could be caused by SPAM complaints and hard bounces. Be sure to remove all spam complaints, hard bounces and unsubscribes immediately and do not email them again. These actions are looked upon favorably by ISPs.

It is important to note that if you have been engaged in cold email marketing and have developed a bad sender reputation, a footprint can be created that will cause you to be blocked quickly based on certain keywords in your domain or content. For example, if you have been sending email blasts with the domain and you change it to or, spam trappers and ISPs can decide that this is spam based on the reputation associated with these keywords and similarity of email content.

The harsh truth is ISPs and spam trappers can block your content for a variety of reasons and don’t always get it right. Even legitimate emails have been known to land in spam folders. Some reasons for your messages being blocked are: 

INTERNAL smtp; 550-5.7.1 [ 54] Our system has detected that this message is 550-5.7.1 likely unsolicited mail. To reduce the amount of spam, 550-5.7.1 this message has been blocked. 

INTERNAL smtp;550 5.7.1 [105.90.110. 93 .26] Our system has detected that this message is likely suspicious due to the very low reputation of the sending domain. To best protect our users from spam, the message has been blocked.

INTERNAL smtp; 421 4.7.0 [TSS04] Messages from 168.1368.12.103 temporarily deferred due to user complaints –;

When these problems occur, it’s best to stop sending email blasts and fix them before continuing with your campaigns. 

Building your Sender Reputation

ISPs alone decide if and when to deliver your email blasts to inboxes. They work with spam trappers to determine your reputation and sender score. Opens, clicks and proper authentication have a positive effect on your reputation. The more bounces and complaints you have, the lower your reputation will be. Some ISPs rely on the reputation of the domain while others value the IP reputation when determining your sender score. Be sure to follow email best practices for email content creation and the deployment of your cold email blasts. 

Things to remember

Your sender reputation cannot be transferred from one IP to the next. If you change IPs, you have to start the warm-up process all over again.

If you are using a domain previously used for sending an email blast and it has a bad reputation, that reputation will follow you. New IPs will not improve your inbox delivery.

Move recipients who have clicked on your messages and not complained or unsubscribed to a new list. These recipients have shown an interest in your messages and may be open to opting in to receive more communications from you. 

Put email blasts to work for your business.

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