Vladislav Podolyako
Jul 20, 2021
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Whenever your messages start landing in the spam folder systematically, don’t fool yourself: it wasn’t a minor issue that led to this. It was a set of errors that emerged at the core of your email outreach and affected your entire campaign

Thus, if you want to prevent this scenario or know how to nip problems in the bud, you must learn to look at foundational elements of your email marketing and see how they can be compromised. To be more particular, we’re talking about domain reputation. Naturally, we’ve mentioned this subject before, but it’s high time we went into detail and highlighted the following:

How does domain reputation work?

To characterize domain reputation in the simplest way possible, it’s email service providers’ opinion about your domain. When they have a good opinion about your domain, they allow its emails to reach recipients’ inboxes. However, if their opinion about your domain is negative, they would scrutinize your outreach on every step. Even a slightest deviation from the guidelines would be enough to consider you eligible for being blacklisted. 

With low domain reputation, your email will reach a spam folder at best. At worst, it won’t even be allowed to proceed. 

But all opinions are built on something, right? We make our opinion about the person based on their actions, looks, and behavior as well as their interactions with other people. The same goes for domain reputation. 

Number of emails sent to invalid email addresses

What do we think about someone who spends their days doing mindless, senseless things, like knocking on the doors of abandoned houses? We think that it’s not our place to judge, but we still prefer to keep our distance or we get suspicious and alert the authorities. 

Email service providers stick to the latter scenario. When a domain starts sending multiple messages to addresses that no longer exist, this behavior makes no sense outreach-wise. However, spammers don’t follow the rules of healthy, legitimate email marketing. They launch massive campaigns to all addresses they can get their hands on. It doesn’t matter whether their domain gets banned or not, they change those like gloves. The only thing that matters is getting as many recipients involved with their shady schemes as possible. 

Therefore, when email service providers notice this pattern, they don’t treat it positively - and you pay the price with your domain reputation. 

Spam complaints from users

What do we think of someone who doesn’t know that ‘no’ means ‘no’ and keeps forcing their harmful presence on us?

“What a horrible person!”

What do we do when such people cause too much trouble and we’ve had enough of them? We report them to the police and they issue a restraining order. 

In email outreach, things work approximately the same. No recipient has to deal with spam messages and spam content. Everybody deserves the right to keep their mailbox clean and safe from obnoxious senders. Therefore, every user can submit a spam complaint when they encounter a set of messages that look suspicious or keep coming in spite of multiple requests to stop and leave them alone. Email service providers will take this spam complaint into account and put it on the balancing scale against your domain

Email authentication

What if we meet someone who refuses to introduce themselves, keeps providing false information about their life, or uses an obviously fake ID? We feel uneasy and don’t speak to such people. For all we know, they can be criminals trying to get in our good graces just to use our trust against us. No, thanks. 

Email service providers follow the same logic. They use a set of checks that allow them to authenticate all incoming emails and determine whether the domain that sent them belongs to a legitimate sender. These checks include scanning the records of a Domain Name System (DNS records) that contain information about the domain and its mail processing guidelines. A proper sender makes sure to instruct the receiving servers on how they can authenticate their messages and what they should do if some messages aren’t authenticated properly. 

Domains that fail to provide such an instruction or any ways to check their legitimacy instantly experience a drop in reputation. 

Volume and frequency of email outreach

How much time do we need to consider someone our friend? It certainly doesn’t take days. Also, the quantity of our conversations with someone doesn’t equal our level of trust with that person. So, a new domain doesn’t become credible by sending thousands of emails within a week. Quite the opposite, such a domain becomes suspicious and bannable. 

The structure of email outreach doesn’t like fast and furious, sporadic and random. It prefers predictability, stability, and clarity. If you don’t meet these requirements, it won’t benefit your domain reputation.  

Does domain reputation affect deliverability?

Considering the factors that reduce domain reputation, the more unreliable, untrustworthy, and unpredictable your domain looks to Internet service providers, the fewer reasons they have to let it interact with other domains and services. 

Accordingly, low domain reputation means a higher bounce rate, fewer delivered emails, and lots, lots of spam complaints. Meanwhile, high domain reputation means next to zero friction experienced in your outreach and more recipients interacting with your messages.

Conclusively, key deliverability factors depend on your ability to behave:

  • Don’t tempt users to report you to the authorities.  Reduce all risks of being marked as spam by your recipients. Your subject lines mustn't be misleading or deceptive, your message shouldn’t contain attention-grabbing slogans written in caps or overflow with images and links. Most of all - back off when your users ask you to. Your recipients decide whether they want to continue the conversation or not. If they want you to leave them alone, they have that right. Respect it and let them go their own way. That includes removing them from your list of recipients once you get the first “Leave me alone!” email and cleaning your list from non-responsive email addresses. 
  • Make it easy to authenticate you. Internet service providers won’t waste their time trying to glean information about your domain. You don’t have records? Your SPF isn’t built the right way? You don’t have a DMARC policy? Well, it seems like you didn’t want to participate in outreach in any way, so welcome to the blacklist. Think of it as if you were crossing the border: you’re asked to show your papers and ID. If you refuse to do so or give a piece of cardboard instead of a proper ID, the customs will deny entry. Internet service providers are no different in that regard, so you must ensure that they can view your DNS records and implement as many transparency mechanisms as email marketing guidelines oblige you to. 
  • Keep your pace steady and stable.  Don’t try to figure out the best time for sending emails as you go. Explore your recipients’ curriculum and pinpoint the best time and day for reaching out to them. It’s the same as calling someone you haven’t met: you need to make that call, but you also don’t want to inconvenience anyone, so you take note of that person’s schedule and see when they are available for a chat. Once you outline the best time and day, be consistent. Erratic campaigns that send a different number of emails every day aren’t favored by Internet service providers.

How is domain reputation calculated?

Email service providers and Internet service providers have the clearest image of your domain reputation. Using complicated algorithms, they analyze your messages’ performance and see how often they get delivered straight to the recipients’ inboxes. These algorithms allow Internet service providers to come up with an appropriate score for the sender’s domain. 

This data is shared between other major Internet service providers that refer to it upon receiving the message from your domain and decide how far they can allow this message to proceed. 

The most complex part about it all is that your domain reputation consists of your domain’s interactions with different Internet service providers. You have a stellar relationship with Gmail, have all your messages delivered without setbacks, but if you struggle with getting your message past Outlook’s defences, your ultimate Sender Score would be below average. To lift your domain reputation up, you have to focus on improving your engagement with all mail services you work with.

How to improve domain reputation?

First of all, let’s try to figure out how your domain reputation could have gotten worse in the first place. Here is one of the most common scenarios. 

An employee creates an account at an online store using their work email. Sometime later, that employee doesn’t work at the company, but their business email account is still active - and it still receives emails but doesn’t respond to them or interact with them in any way. The spam filter used by the former employer notices this activity, marks it as suspicious, and reports the entire domain. 

There you have it. The damage is done. It could have been prevented if the employee had unsubscribed before leaving, but it won’t do the company any good to think about what could’ve been. They need to work with what they have.

  • Look alive. No matter how many mailboxes you have, don’t let them get stagnant. The engagement rate goes both ways: it depends on how recipients interact with your emails and how you treat messages that you receive. So, if you’re subscribed to any newsletters or services, make sure to open and mark emails as read. Don’t let irrelevant messages pile up in your inbox and sort your mail by the end of your working day. 
  • Say “no'' to stealthy opt-ins.  Have you ever created an account on a website and instantly found yourself subscribed to a newsletter? It feels bad. Disrespectful. Deceiving. Some people got used to it thinking that this is how marketing works and it can’t be fixed. However, real marketing, especially B2B marketing, doesn’t need such an approach. It’s built on transparency, honesty, and recipients’ consent. Instead of trying to trick people into subscribing, you actually let them confirm that they want to subscribe by providing a double opt-in feature. 
  • Validate your subscribers. Use validation tools or turn to professional validation experts who would help you clean your sending lists from inactive and passive users. It will let you ensure that you work with responsive recipients only and save some businesses from spam-related issues. 
  • Don’t use shortened links. They look nice and clean but they have been abused by spammers and hackers. With a shortened URL, it’s quite easy to create misleading content and trick recipients into clicking the link they never intended to. This is why spam filters treat such links with suspicion. 

The sad truth is, you can’t predict all reasons for low domain reputation. It’s physically impossible to stay in control of everything. 

What you can really do is build a troubleshooting plan and stick to it. 

Step 1. Use tools for tracking domain reputation

Nowadays you’re not in shortage of services, platforms, and tools that let you view your stats and evaluate your performance. Of course, none of them allows you to peek into the private data gathered by Internet service providers, but with the information they provide for each of your metrics, you are more than equipped for tackling domain reputation problems. 

For example, Folderly lets you run email deliverability audits for your domain and your mailboxes, so you could track your general progress and see the engagement rate of each inbox. This audit includes:

  • Open rate tracking 
  • Click rate monitoring
  • DNS records check
  • Blacklist scanning 
  • Volume of emails sent
  • Number of emails delivered
  • Email placement with different email services

By taking all this data into account, Folderly calculates your current Sender Score and shows how well your domain is doing.

With Folderly, you can view the most important metrics in one place, without having to use several tools or check one mailbox multiple times. 

For more options, you can view our selection of tools for mailbox audit in this post

 Step 2. Do an IP address warmup 

Internet service providers monitor the activity of each IP address. If they detect any suspicious activity coming from your addresses, you have to make it up by proving that you’re a legitimate sender who sticks to a healthy schedule. 

If you use a dedicated IP (the one that belongs to you and you alone) and not a shared IP (those of other users not related to your company), you’re the one in charge of your reputation. When you know that some of your mailboxes are compromised, the best you can do is start building a healthy outreach pattern, one email at a time. 

  • Start with sending a small number of emails to the recipients who are guaranteed to interact with your messages. Make sure your recipients mark your emails as “Important” after opening and reading them.  
  • Gradually increase the number of messages you can send. Check your performance with a testing tool to see whether it’s time to expand the sending volume.
  • Keep up with the limits of your email service. Not all mailing services are designed for sending extremely large batches of emails. For example, you can send around 2000 messages per day with Google Workspace and around 10000 emails with Office 365 email (but do mind that you can send no more than 30 messages per minute!). If you work with different email service providers to connect with a large target audience, you have to remember about each email service’s strengths and weaknesses. Otherwise, you’ll end up making a mass out of your outreach and domain reputation. 

Step 3. Respect email authentication protocols

By email authentication protocols, we mean:

SPF record

Basically, it’s the ID that your domain (and third-party domains included in your outreach campaigns) carry around and show whenever they interact with a receiving server. When the receiving server reads this ID, it obtains the following information:

  • Domains and IP addresses that belong to you and can be trusted,
  • Email services and apps you use for your outreach campaigns,
  • List of records (A record, MX record, PTR record) that recipients can check.

When a malicious sender tries to disguise their harmful email using your domain name, they won’t get far, because they won’t have your SPF record and, therefore, won’t be able to prove that they’re connected with you in any way. So, it’s a very important record to have. Also, it’s a very complicated one. Usually, an SPF record is generated automatically, but as your outreach grows and becomes complicated, you may face the need to make some adjustments. Mistakes, such as creating a duplicated SPF record or misplacing a syntax aren’t uncommon so our advice is - don’t do this at home. You can use an SPF record generator to build the perfect record or ask an expert to guide you. 


An SPF record isn’t the only email authentication protocol guarding your email against spoofers. A DKIM signature is its trusted partner when it comes to ruining spoofers’ plans. This encrypted signature is placed into the header of your message and is visible only to the receiving server. A DKIM signature cannot be forged or copied, it’s unique for each domain. Whenever a server gets an email and sees such a signature, it’s a clear sign that the email hasn’t been not tampered with and can be moved straight to the inbox. 

A DKIM signature consists of a key pair: a private key and a public key. The private key is attached to the message header and validated by the receiving domain. The public key is stored in your DKIM DNS record and used by receiving servers to authenticate and verify your private key. 

If you use Gmail, your messages are protected by a default DKIM. Given the high defense protocols of Gmail, it’s more than enough in most cases. However, if you want a more individual and polished version of the DKIM signature, you can generate one on your own. You have to log in to your Google Admin Console, choose your primary domain, and then click Generate new record. Keep in mind that you have to choose the following:

  • Key bit length. The system will offer you to generate either a 2048-bit key or a 1024-bit key. The first one is more complicated and thus provides more protection, so unless you’re restricted to 1024-bit keys by your domain host, go for the 2048-bit length. 
  • DKIM prefix selector. It’s a string of text that directs receiving servers to the place where the public key data is located, allowing them to check and verify the DKIM signature. For example, the default DKIM prefix selector for Gmail directs to “google”. 


A DMARC policy is an extra measure for managing email networks and making it easier to identify inbound emails. It contains a set of policies about email authentication and guidelines for handling emails that failed all authentication checks. DMARC authentication is in charge of scanning the sender’s SPF record and DKIM signature, checking domain records and ensuring that the incoming message is good to go. It’s also responsible for quarantining suspicious email. 

A sender’s SPF record and the recipients’ DMARC record have an important synergy, since the DMARC scans the mechanisms mentioned in the SPF record (particularly, the instructions on managing unidentified email) to determine whether to quarantine the message or block it completely. This measure allows you to minimize fishing and guarantee quick, productive authentication reporting. 

Having a DMARC policy is a must for you as a sender, because in addition to ensuring your safety and accelerating your performance, it is also a necessary measure that is monitored by Internet service providers. 


It takes a lot of time and effort to build a good reputation for your domain. Well, it’s no different from building a personal or professional reputation. You can invest months and years in it, but it would crumble in a day because of one mistake. However, we hope these tips would allow you to get more control over your domain reputation, learn how to boost it, and avoid most of the things that bring it down. Sometimes it will be threatened by the factors you can’t really control. You only have to stay vigilant and pick the right troubleshooting tools. If you’re curious about how your domain reputation is doing right now, you can reach out to Folderly's experts

Vladislav Podolyako
Vladislav Podolyako
Founder & CEO
Vlad’s decades of entrepreneurial wisdom and business building experience have allowed him to successfully mentor a diverse group of business owners, entrepreneurs in growing their companies. A recognized expert in the areas of transforming organizational culture and leadership development, B2B Sales, Marketing, spent more than 10 years building technology products, with a background in communication networks and electronic device engineering.

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