Page tree

There are various reasons why emails are not delivered, and figuring out why can be somewhat of a mystery. The good news is that with a little investigation, you should be able to improve your email bounce rate.  

Before you read further

If you haven't already requested a list of email addresses that cannot be delivered, let's do that first. 

  1. Gather a list of each sender's email address you want to check. 
  2. Call our support team at 1-800-669-2509, option 1.
  3. Our team will help you access an online form where you'll enter each email address you want to check. The list will be emailed to the inbox for each email address. 

An Email's Journey from a 30,000 Foot View

When you write an email and press send, your electronic communication travels across several types of servers and domains. They are all designed to translate the human-readable email address into something computers understand (example-72.457.89.544). This system of servers and domains are a part of the internet, and their job is to ensure the message makes it's way to the right person's email account. At the end of journey, a human or a personal device must "fetch" email either manually or automatically from the user account before it is readable. For the most part, this journey goes off without a hitch. But sometimes, servers are down or email accounts are closed or full. When this happens, email is added to a transport list. These are called "bounces".

Types of Bounces

There are two main types of email bounces:
  • Soft bounce - a soft bounce means the email address is correct and it was delivered to the recipient's inbox, but it still bounced because the mailbox is full, the server was down at the time of delivery, or the message is too large for the inbox.
  • Hard bounce - a hard bounce occurs when an email is permanently rejected because the address is invalid or doesn't exist.

The Most Common Reasons Email Bounce

  • The recipient's email address contains a typo or doesn't exist. The person may have closed the account, left the organization, or provided a false address.

  • The email isn't deliverable because the receiving email server is temporarily unavailable or overloaded. If the email continues to bounce, it may mean the server is gone forever.
  • Inbox is full or the size of the email or attachment is too large to fit in the inbox
  • The recipient has their email set to "Vacation/Auto-Reply". The email was delivered to their inbox, but you will still receive a "undelivered" notification. If this continues for months on end, you may want to remove the contact.
  • A receiving server may block email and place it in a "blocked" category. You're more likely to see this when communicating with corporate, educational, or government institutions. The recipient will either need to ask their employer to unblock the email or provide you with an alternative.

Email that cannot be delivered (aka bounced email) has a negative impact on the success of an email campaign and erodes confidence in communication between a church, parish, or other organization and it's members. If you have email addresses that bounce repeatedly, consider removing the option to send email to this particular address while you're investigating the problem or attempting to contact the recipient.

Safe Senders List

Once you've investigated and resolved an undelivered email issue with your contact, our support department can facilitate adding the email to a safe senders list. This restores your ability to send email to the address. We'll send your contact an email from a different server. Your contact must reply to the email before we can assist.


Bounced Email -Any email message that is not delivered to the recipient and is returned or "bounced" back to the serve where it originated, or the sender.

Transport List - A list of email addresses that cannot be delivered for various reasons.

Blocked Senders List - Block lists are lists of email addresses that can no longer be trusted. This may also be referred to as "blacklisting" an email.

Safe Senders List - A safe senders list is a list of email addresses that will not be blocked by the application or server. Some people refer to this as "whitelisting".