Part 2: Eloqua email deliverability: Who is involved?

Aug 25, 2021

This is part 2 of my Eloqua email deliverability series.  I strongly advise you to read Part1. What is the object of Eloqua email deliverability? if you already have then crack on….

Greg Staunton

Three parties are required to get an Eloqua email into the recipient’s inbox: senders (i.e. the company sending the email), gateways (the companies that enable the sending of email), and recipients (i.e. the customer).

Eloqua email deliverability
Email Senders

Generally speaking, email senders fall into three categories: legitimate email senders, email certification providers, and spammers:

  • legitimate email senders have a valid reason for sending emails. For example, it could be sending transactional emails, marketing emails, newsletters, or more.


  • Email certificate providers aren’t exactly senders, they can help you send emails efficiently and bypass ISP filters. These companies usually have good relationships with ISPs and provide vouch for you as a sender.
  • Spammers are those who send a lot of unsolicited messages to a lot of people, usually in large numbers. It can be malicious (for example, sending malware or phishing emails), or just annoying. This is why ISPs must monitor spam messages closely.


Email Gateways

Generally, there are two types of gateways: major ISPs and smaller companies (including smaller regional providers). The gateways control whether your emails get delivered.  Blacklisting systems and anti-spam systems will also be included here.

  • Major ISPs deliverability-wise are what you should be most concerned with. If you can accomplish deliverability with them, you should also be fine with minor ISPs regarding Eloqua email deliverability.
  • Minor ISPs typically use the same algorithms used by the major ISPs to monitor email sending because they purchase and tweak them so they have a unique selling point for a specific industry
  • B2B anti-spam systems are difficult to understand because each business configures its own systems, so it’s very difficult to provide deliverability guidelines.  This can be a show stopper for Eloqua email deliverability.
  • Blacklisting organizations are something that will seriously affect Eloqua email deliverability, if you fall foul of them you end up on one of their lists, which means you need to make removing yourself from it your top priority, if you do. All major ISPs use these reports, so you don’t want to end up on one.


Eloqua email recipients

Your goal is to reach these people, and the ISPs want to protect those people from spam. If you want to get your Eloqua email delivered into their inbox, you need to understand the tools they use to fight spam.


How can ISPs affect Eloqua email deliverability?

In order to keep spammers away from your emails, your ISP employs a number of methods. However, because they must manage mass amounts of email, these methods can also affect your Eloqua email deliverability. Let’s look at which tools are available, and how you can use them to your advantage.

Eloqua email deliverability
Eloqua email sending limits

In order to determine how much email you may send in a set amount of time, ISPs establish sending limits. These limits are the total amount of Eloqua email you may send within a specified period.  Upon reaching your daily sending limit, ISPs soft bounce all your emails afterward until the limit is reset.  Depending on how frequently you send emails from Eloqua, you might have a daily or weekly sending limit. If you send emails once or twice a week, your weekly limit might be greater than your daily limit.  It depends on your sender reputation how strict the limit is. If your sending volume spikes, your emails will get soft bounced, no matter how good your reputation is.

Soft bounces can be avoided by gradually increasing your Eloqua send volume.

You should get your email volume ramped up at least 30 days before a massive Eloqua campaign to your global list. This is done by gradually increasing the number of emails you send so you reach your goal as soon as possible.  This can be achieved through Eloqua email throttling.


Blocked Eloqua email sending IP address

Blocks make it impossible to send emails. Not good. ISPs typically block senders after they receive too many spam complaints or after they hard bounce too many emails.  In general, blocks last between two days and one week, although sometimes they are indefinite.


What to do if an ISP blocks your Eloqua emails

In some cases, you must contact an ISP and show them that your email sending practices have changed. For instance, you may need to show that you have reduced or added new audiences to your mailing list.

As a rule of thumb, it is better to prevent ISP blocks than to attempt to rectify them.  To avoid spam complaints, make sure your mailing list is clean to prevent hard bounces, segment your mailing list so you’re only sending Eloqua emails to engaged customers, and make unsubscribing as easy as possible.


Email bulking

Bulking means that ISPs will automatically send your email to spam or junk folders. Because most people don’t regularly check their spam folders, your email may not be seen.


When you send an email, how can you tell if it goes to spam?

Eloqua doesn’t allow you to detect if an email is going to spam with Dashboards or Insights. However, you can analyze a 3rd party mail analytics report to find out if the email is going to spam.  Create a report that shows open and click rates broken out by ISP. Next, check if you see a sudden drop in both rates for one ISP, but not for the rest. That’s strong evidence that your emails are going to spam folders.

An Eloqua ISP seed list is another option. This is a collection of hundreds to thousands of email addresses that you can verify get used by different ISPs, you could maybe even develop an Eloqua program that uses match rules which in turn will set ISP on a separate contact or custom object record field so it’s possible to see the way various ISPs are dealing with your emails.

In terms of implementation, Eloqua ISP seed lists shouldn’t be used to warm up new IPs. Because accounts on seed lists don’t show any engagement, they may negatively impact reputation and cause Eloqua email deliverability to decline.



It’s a more severe form of a block, which lasts until the blacklisting organization removes you from the list. IP addresses listed on blacklists cannot send Eloqua email to ISPs that filter mail by using that blacklist.

The best way to avoid winding up on a blacklist is to avoid being placed on one. If you find yourself on one, you should make it your number one priority to get off of it.


Which attributes do ISPs view as negative or positive?

Eloqua email deliverability decision is binary ISPs. There negative behaviors and positive behaviors.  If you minimize the negative while maximizing the positive, you’ll be able to deliver more Eloqua emails.

Eloqua email deliverability decision is binary ISPs. There negative behaviors and positive behaviors.  If you minimize the negative while maximizing the positive, you’ll be able to deliver more Eloqua emails.

Negative attributes

It’s important to avoid both hard and soft bounces. A hard bounce indicates that you don’t have a clean email list, while a soft bounce implies inconsistency in your send volume.

This is a big problem in the eyes of ISPs. They have a very low tolerance for spam complaints. Please set a threshold for spam complaints that is less than 0.1% and strictly adhere to it.

It’s a big negative signal to ISPs choosing to send Eloqua emails to spam trap addresses, which you shouldn’t be sending them. There are two types of spam trap addresses:

  • Pristine email addresses
  • Recycled email addresses

In terms of email addresses, pristine addresses are brand new accounts added by spambots to your list. Recycled addresses, on the other hand, were reclaimed by your ISP after 180-270 days of inactivity.

When your Eloqua email hits pristine spam traps, you have bad mail collection habits, and if you hit reclaimed addresses, you haven’t cleaned up your mailing list.

ISPs can observe when subscribers treat your Eloqua emails as read, or delete them without looking at them, so it indicates to them that the content is potentially spammy, as such, it will damage your reputation. It generally won’t be as bad as being marked as spam, but it won’t be as good as good either.

Positive attributes

You should encourage this as it is a very notable action. It shows that the recipient wants your Eloqua emails, and it makes you look really good. It has a very low conversion rate (as little as 2%), but when you encourage it, it can greatly enhance your reputation.

The body of your email should include a line that says something like “Add our address book to stay updated with our latest whitepapers” This is especially effective when you send out really high value content.

We’ll discuss this more below. Good senders send emails that are opened and clicked on.

ISPs see this as a positive, as people forward content they find interesting.

Responses mean engagement, and engagement is good. In fact, ISPs look negatively on recipients not being able to reply, so avoid that at all costs.

What is a good open rate for your Eloqua emails?

You might experience delivery problems if you do not have good open rates, so how can you figure out what works well? We can think of open rates like online reviews; they can range from 5 stars (excellent) to 1 star (not ideal).


Eloqua email deliverability issues occur when you hit an open rate below 20%.

When your open rates fall below 20%, you’ll have problems.  Open rates below 10% indicate fundamental issues with your mailing list or your content. If you’re in the 15-19% range, you may occasionally experience deliverability issues. From 10-14%, you may have lots of issues, and you’ll need to work hard to improve open rates.

In case you have a good open rate but are still experiencing deliverability issues, you can try adjusting some other elements.

Now that you know everything there is to know about who is involved with getting your Eloqua email into an inbox, let’s dive into Part 3. Eloqua email deliverability factors that you control.
Greg Staunton

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