How to Fix the Mailchimp Omnivore Warning

So, you’ve written a perfect email, tested it, geared up to finally send it... and, there’s a big red cross with a ‘warning’ message stopping you. It’s frustrating.

We’re here to help. In this post, we explain:

• What the Mailchimp Omnivore warning is, and why it’s stopping you from sending emails
• How to resolve the issues with email list management 
• Some real-life examples of how we helped fix Omnivore warnings 

Our clients had this exact problem. They got a huge email list, and when they tried to import it into MailChimp, it got rejected. It was too much for them to clean manually, so we did it for them. To learn more about how we can do this for you in a fraction of the time, contact us for a free consultation.

What triggers a MailChimp Omnivore warning?

This is where it gets tricky. Omnivore doesn’t tell you exactly what the issue is, and it won’t highlight which addresses have alerted their triggers of a ‘bad’ email contact.

Mailchimp Omnivore uses an algorithm to predict audience behavior on email addresses, based on the group of addresses in each send list. They assign a level of risk, and when this reaches a certain level, they prevent you from sending emails to them.

Omnivore warnings are usually given when email addresses are considered to be inactive or spammers. 

Here’s what might be causing an Omnivore warning:

• Possible spam traps on your list
• Addresses that may cause hard bounces
• Addresses that could generate abuse complaints

We put together a helpful post with 10 essential best practice for email list hygiene.

What is a spam trap?

Spam traps are inactive or invalid email addresses, set up by Internet Service Providers (ISPs) or anti-spam organizations. They are designed to catch out companies that send bulk emails to decayed contacts, or those they don’t have permission to email. New spam traps are created frequently and can end up on lists, even without the intention to ‘spam’.

As they are inactive or unattended, they are never opened or interacted with, and they never opt-in to anything. They therefore negatively affect your sender reputation. They can affect your email service provider’s sender reputation too if you aren’t using a dedicated IP for email sends. This is why Mailchimp blocks you from sending emails if they believe your list contains spam traps.

They can be managed by regularly cleaning your data, and monitoring your audience engagement.

What is a hard bounce?

A hard bounce happens when an email is undeliverable to a particular email address. This could be because:

• The recipient email address is incorrect or doesn't exist (for example, it contains typos or incorrect symbols)

• The recipient email server has completely blocked delivery

Omnivore will block sends if your list contains an address it identifies as being unable to send to, to protect their server’s sender reputation. 

In 2019, Mailchimp revealed in an Email Marketing Benchmark study that the average hard bounce rate across their email sends was 0.40%. They should be a rare occurrence and can be managed by maintaining a healthy email list.

What are email abuse complaints?

You’ve probably made one. It happens when someone clicks ‘mark as spam’ in their email inbox. If it happens to one of your emails, that’s bad news, but it can happen, even when sending legitimate emails to a subscriber. 

If it starts happening frequently, then you may start to have issues with your email service provider. Mailchimp suspends accounts if the amount of spam or abuse complaints go over a certain threshold.

Omnivore looks out for the potential of this happening, based on its data and its algorithm, and prevents the email from being sent before it can happen.

Cleaning up your list

1. Check your opt-ins
   If your contacts aren’t properly opted-in, then you’ll run into problems. This could be because your list is old, or perhaps you’ve bought or borrowed the contacts. Omnivore may show a warning if you have imported contacts without proof of opt-in, especially if you must comply with strict GDPR rules.

   
   

2. Clean your data
   As we mentioned, incorrect email addresses cause hard bounces and will be picked up by Omnivore. Human error happens, so review your email list and look out for typos and keyboarded misses.
   
   Depending on the size of your list, this can be a lengthy task. We’ve estimated that it takes a human about 3-5 minutes to clean one data point. You may want to outsource to data cleaning tool, who can help you with using validation methods and spotting potential errors.
   
   Check out our real-life examples of email list cleaning for Mailchimp Omnivore later on in this post.

3. Have you stayed in touch?
   Once you’ve ensured that you have permission to email these contacts, and the addresses are all correct, look at how long you’ve had your lists. Have you emailed them frequently? If your list is old, and you haven’t contacted them in a while, or ever, they aren’t guaranteed to be active contacts.

4. Review the data you have
   If you have previously emailed these contacts on Mailchimp or with another ESP (email service provider), review the data you have on their engagement. If they’ve never opened or engaged with an email, or if you’d received a spam complaint from them, you’re better off removing them from the list to stay on the safe side.

How we helped real businesses overcome the Mailchimp Omnivore warning

Here at tye we help our clients achieve more effective email marketing by cleaning their lists and helping them to improve their list hygiene. Although we help customers regardless of email marketing tool, we’ve responded to some Mailchimp Omnivore specific requests.

Mailchimp is the market leader, which means they are the go-to when it comes to email marketing. They attract a lot of users that might be new to email marketing. Often, that means people who aren’t aware of best practices and could unknowingly make mistakes. 

When this happens, due to the shared server sender reputation, Mailchimp pays the price. Their rules are strict, but it’s understandable.

When helping clients to resolve the Mailchimp Omnivore issue, we typically run email validation and data clean up tasks. 

An email validation service uses technical means to assess whether an email is deliverable to a certain address, or not.

Data clean up is when we look at addresses that appear to have errors. By doing this manually, we can ‘fix’ addresses that are correct, but just written wrong, rather than considering them to be invalid and having to remove them.

We look out for spelling mistakes and character mix-ups. Examples we’ve seen are ‘.ocm’ instead of .com, a ‘2’ instead of an @ symbol because of the keyboard placement in certain regions. We look out for typical errors or symbols that aren’t used in email addresses, as well as possible typos.

We also look for naming errors, for example when the first name and last name assigned to the email address doesn’t match up.

Once this is done, we use at least 2 different data validation tools to review your lists. They all use different methods, so using multiple tools allows you to cover as many possible errors as possible. We prefer to err on the safe side, so we don’t require all the tools to flag a contact as a risk. One flag is enough to remove a contact. 

We also check for evidence of opt-in, because Mailchimp asks for this. If you are collecting emails with Mailchimp they have a double-opt-in process, which means bad emails never get added to lists.

Here are some examples of work we did with clients:

Our clients had this exact problem. They got a huge email list, and when they tried to import it into MailChimp, it got rejected.

It was too much for them to clean manually, so we did it for them. To learn more about how we can do this for you in a fraction of the time, contact us for a free consultation.