Meta pixel
What is AWS?
What is Amazon SES?
What is an AWS Region?
Check reputation metrics of your AWS account
What is Amazon SNS?
Why do you need Amazon SNS?
Connecting AWS account with MailBluster
AWS Account Payment and Free Tier Details
AWS account credit card requirement
Website requirement for AWS account
Additional cost for using Amazon SES
Choose AWS region for MailBluster
Move out of Amazon SES Sandbox
Using MailBluster when AWS Account is in sandbox
Amazon SES Sandbox and it’s restrictions
Amazon SES sandbox removal request rejection
Resolve error: ‘Unable to connect with Amazon SES using your AWS account’
Recipient address on Amazon SES suppression list
Manage IAM users across multiple brands in MailBluster
Verify domain in Amazon SES
Verify email address in Amazon SES
Verify sender domain from MailBluster
Verify sender email address from MailBluster
What is a Sender Identity?
Remove email ID from the sender list to improve deliverability
What is a Custom Domain?
Set Custom MAIL FROM Domain in AWS
Importance of setting up custom mail from domain for DMARC alignment
Why set custom mail from domain in Amazon SES?
Configure a custom domain or subdomain for tracking
Prevent gmail from showing ‘via amazonses.com’
Reasons your AWS account gets paused and how to fix it
Resolve AWS account pause issue
Achieve positive sender reputation for new domain
Resolve error: Unable to find the permission of ‘AmazonSESFullAccess’.
Resolve error: Unable to find the permission of ‘AmazonSNSFullAccess’.
Resolve error: Invalid AWS secret access key
Disable open tracking for all campaigns sent from your Brand
Resolve error: “We couldn’t find required configuration to track your email activities using your AWS credential”
Fix DMARC alignment and SPF issues in Amazon SES using a custom mail from domain
Gmail is not showing one-click unsubscribe (list-unsubscribe header)
Does AWS show complaint rates and bounce rates for AWS accounts?
How to find details of a recipient complaint in Amazon SES
MailBluster and how it works
Features of MailBluster
What is Email Marketing?
Why use MailBluster with AWS for sending emails?
Features of the Starter Plan
Features of the Pro Plan
MailBluster Daily Email Sending Capacity
MailBluster is still giving a message to move out of sandbox
Can you send test email in AWS Sandbox with MailBluster?
Send Test Email after exceeding free email limit
Didn’t receive verification email from MailBluster?
Does MailBluster have domain tracking?
Does MailBluster provide secured and reputable IP addresses?
SMTP settings in MailBluster
MailBluster support Custom SMTP
Can MailBluster be self-hosted?
Does MailBluster have Autoresponder?
Sending Transactional Emails using MailBluster
GDPR compliance in MailBluster
Resend verification OTP from MailBluster
On which platform is MailBluster built?
Customize MailBluster Cookie policy
Character Encodings Supported by MailBluster
Does MailBluster support Email Attachments in email campaigns?
Maximum Email Content Size in MailBluster
New Lead Feature in MailBluster Dashboard
Purchase Activity in MailBluster Dashboard
White-Label solution
Sending cold emails using MailBluster
MailBluster Bug Bounty Program
MailBluster support channels
Official legal address of MailBluster
MailBluster Affiliate Program: How It Works and Earns You Commissions
Sign up for MailBluster Affiliate Program
Is there any cost to join the affiliate program?
Benefits of MailBluster Affiliate
MailBluster Affiliate Program Eligibility
Fallback for Leads Without First Names in MailBluster
What is a Campaign?
Edit Campaign in MailBluster
Rename campaign in MailBluster
Duplicate campaigns in MailBluster
Schedule campaign in MailBluster
Edit scheduled campaign in MailBluster
Cancel scheduled campaign in MailBluster
Archive / Unarchive Campaigns
Change the width of campaign email
Maximum email content size limit
Reason of emails being clicked automatically
Using query string in campaign
Remove MailBluster branding
Why MailBluster campaign sending takes time
What is double opt-in?
Send quick test email before campaigns
Send Test email using Merge Tags
Configure Double Opt-in in MailBluster
Difference between Standard Campaigns and Automation Campaigns
Send Campaign in plain text in MailBluster
Create and Send an Email Campaign
Send Personalized Email from MailBluster
Compose email using Drag and drop editor
Share email campaign from MailBluster
Add Unsubscribe link using Drag and Drop editor
Add Unsubscribe link using HTML editor
Add Unsubscribe link using WYSIWYG Editor
Email campaign is showing “outdated”
Campaign still in the “waiting” status
Resolve Error: “Link/URL used in campaign content must be a maximum of 1000 characters long”
Warm up a new subdomain for large email audiences
Store images in MailBluster
Display a sender image in email campaign
Maximum file size of an image file
Add strikethrough in the subject line of email campaign
Add motion logo in email campaign
Text looks broken in campaign despite appearing fine in the editor
Use UTM for tracking in MailBluster using Google Analytics
Exceeding the email sending limit in MailBluster and its impact on campaigns
Resolve “Content is invalid, merge tag or block tag contains error”
Resolve “AWS connection is invalid” under the Sender email address
Short preheader text in email campaigns automatically populates
CTA Button URL is Showing 404 Error and Redirecting in Test Mail
Use Default Merge Tag in Email When Data is Missing

Resolve IP blocks that hurt email delivery and open rate

Last update: August 31, 2025

If you want to resolve IP blocks that hurt email delivery and open rate, it’s important to understand why these issues occur. Based on our work with AWS customers, seeing an IP address on a spam list is surprisingly common. There are several reasons behind this problem, and knowing them will help you fix it.

Why IP Blocks Happen

1. Shared IP Pool
By default, AWS sends emails through a shared IP pool. Other AWS users may have already used these IP addresses, and if they engaged in poor sending practices, the IP may appear on spam lists. As a result, your campaigns can suffer even though you didn’t cause the problem.

2. New IP Address
When you switch from another service to AWS, you start sending emails from a new IP. Email Service Providers (ESPs) don’t immediately trust this IP, even if your sender domain is valid. Therefore, it’s better to start with a small volume of emails and gradually increase sending. This process, known as “warming up” an IP, builds reputation and improves deliverability.

How to Resolve IP Blocks and Improve Deliverability

To resolve IP blocks that hurt email delivery and open rate, follow these actionable steps:

1. You might have an issue in SPF record, so you need to look into it.

2. Improve your email.  Too many images make your email bulky. Bulky emails are tough to deliver and impact deliverability. We have seen customers getting better output by sending simple text emails. It looks like a personal email.

3. Avoid adding any URLs other than your sending domain to your email content. For example, don’t use URL from sendgrid.com or similar.

4. Set Action URL from the Settings > Custom URL section. Add your own domain/subdomain. It will improve deliverability. It’s part of point 3.

5. Personalize your email campaign. For example, it’s better to write Hi {{first_name}}, instead of Hi Guys,. To ESPs, it means you know who you are sending emails to and each email is different.

6. Create email campaigns using drag and drop editor. It creates better HTML code that supports all types of devices and ESPs.

IP blocks can seriously harm your campaigns. However, when you understand why they happen and apply the right fixes, you can quickly improve deliverability. By focusing on authentication, personalization, and sending practices, you’ll be able to resolve IP blocks that hurt email delivery and open rate while keeping subscribers engaged. For more detailed information, you can read this blog: https://mailbluster.com/blog/the-ultimate-guide-on-how-to-prevent-your-email-newsletters-from-going-to-spam. If you can follow this correctly, it would definitely help you a lot.