Bringing Open Rate From 5% To 30% With a Subdomain Warmup

Open Rate
Email Deliverability
EVP of Sales & Marketing

How hard is it to get an inbound B2C email delivered? In theory, it should be a piece of cake. Your recipients are mostly users who gave their consent to receiving emails from you, so building engagement and increasing conversion rate shouldn’t be a problem as long as you keep your inbound marketing content interesting.

In reality, however, there are many conditions to secure the success of your email marketing campaigns. Follow them, and you will get the results you’ve always wanted. Ignore them, and you’ll find yourself struggling with getting your recipients to see you. 

Our client started off at a great pace. An online retail store specialized in selling clothing and working with such brands as AniNadin, Christian Dior and Louis Vuitton across Eastern Europe came across an unexpected obstacle that led to transactional emails never showing up in the users’ inboxes.  

Due to the NDA agreement, our client wished to remain anonymous and, therefore, will be further referred as The Client

Since emails are an important part of communication channels and sales, The Client realized the necessity for professional intervention. 

Breaking point 

“It was maddening. Our website traffic was decent; people interacted with products and added them to their carts...but they didn’t receive any confirmation of their actions, and we couldn’t understand why it was happening. When our website traffic started dropping, we realized we had to do something, FAST.”

The Client had one major issue that hindered business activity and required assistance from the people having expertise with mailboxes and mail-sending mechanisms. 

1) No triggered emails. The users who visited the website and performed such actions as adding a product to the cart, confirming a purchase, never got any transactional emails. The transactional emails notify users about an incomplete purchase or alert them that the product they were interested in is back in stock. 

This issue has affected the revenue and conversion rate. First of all, the users who made a target action were unsatisfied with the inability to track their order status. Second, there was no chance to remarket users who didn’t complete their purchase or were unable to buy the product they wanted because it wasn’t currently in stock. 

Transactional emails are a vital part of any B2C business. By acknowledging users’ actions on the website, updating them about the product that got their interest, and motivating them to complete the transaction, they are your ultimate engagement boosters. Nowadays, they are also a commodity that all B2C customers for used to. Therefore, when users expect to receive trigger emails, but no message arrives, they feel frustrated and no longer wish to interact with the retail website. 


“Folderly’s CEO got in touch with us right away. He explored our issue very attentively, asked us about our email marketing routine, and pretty much explained every email outreach term that we were confused by.”

1. Private consultation. We reached out to The Client to discuss the core issue and investigate when it started happening and how long it took to notice its effect on revenue and conversion. After this, we ran a brief presentation of Folderly’s features, explaining how each of them can help with solving the issue that affected the business of The Client. We also walked The Client through the steps of adding mailboxes and email services to Folderly. 

It’s believed that email deliverability tools make more sense for B2B businesses because they engage in cold outreach, while B2C users usually give consent to receiving emails by interacting with a B2C website or even leaving their contact data upon making an order. However, that’s not true. Mail transfer algorithms evaluate all mailboxes equally, so even if you work in the B2C area, you should still monitor your performance, warm up your domain, and analyze your templates with the help of a user-friendly platform. 

2. Folderly research. After introducing The Client to Folderly and scanning their main domain, we received a report that informed us about the following: 

  • No subdomain. While it’s not a technical outreach error, in The Client’s case, it was the main reason for transactional emails not showing up in the recipients’ inboxes. The Client sent both marketing emails and trigger emails from the same domain instead of creating a separate channel for transactional messages via subdomain.

Marketing emails and transactional emails differ greatly in their style and purpose. Transactional emails build engagement faster because users actually expect to receive them and, therefore, are ready to interact with them. Compared to them, marketing emails need more time to deliver results, so their deliverability won’t be able to catch up to trigger messages. By sending both trigger emails and marketing emails from the same domain, you let their sending reputations overlap and affect the deliverability of your transactional emails. 

Additionally, we discovered other issues that had a negative impact on The Client’s email marketing campaigns. 

  • Wrong SPF syntax. Prior to contacting Folderly, The Client used MailChimp to manage the flow of the emails. However, instead of adding the current SPF record, The Client generated a new one with the help of MailChimp and then merged two SPF records together. It created an extremely long string of characters and mechanisms that was incomprehensible to internet service providers.

When an email marketing service asks you to add an SPF record, you don’t need to generate a new one to meet its requirements. You must always use your current SPF record when adding new tools and services. Some services allow you to edit your existing SPF record and include them in your Sender Framework Policy without any problem; some services require SPF record tweaking before you can incorporate them into your email outreach. 

Due to this SPF record issue, The Client’s DMARC policy wasn’t working correctly. It resulted in recipient servers rejecting the DMARC record and further compromising email marketing. 

The DMARC record is effective only when both the DKIM signature and SPF record are correct and have no syntax errors. When one of those components is flawed, the DMARC policy fails to fulfill its purpose and ends up doing more harm than good. 

3. Troubleshooting. After making sense of the issues that impeded the progress of The Client’s business, we set our course on removing them, one by one:

    • Adding and warming up a subdomain. With The Client’s help, we created a new subdomain dedicated to transaction emails exclusively. This process involved all stages necessary for ensuring high deliverability and a solid engagement rate.  

1. DNS records. We generated a DKIM signature and an SPF record for the new subdomain. For the latter, we used our Folderly SPF record generator to avoid syntax errors and include all essential mechanisms and email services. 

Subdomain doesn’t share a sending reputation with the main domain. It has a separate Sender Score and needs its own DKIM signature and Sender Framework policy to perform correctly. Therefore, whenever you add a new subdomain, you must work in its DNS records and adjust them in a way that fits the purpose of the subdomain. 

2. DMARC policy. With DKIM and SPF records in place, we were able to proceed with adjusting the DMARC policy for the transactional subdomain. Initially, we set the policy to send reports about any messages that failed the authentication check - it was important for polishing our warmup and authentication protocols. 

As you grow more confident about your domain reputation, you can change the DMARC policy and let the recipient server block 100% of messages that fail the authentication check. However, at the earliest stages, you want to receive reports that inform you about when and why some of your sent messages didn’t pass the authentication process. 

3. Subdomain warmup. Just like the main domain name, the new subdomain needed some time to build trust with internet service providers and email services. We started with sending a small number of emails to warm email addresses. The recipients interacted with each message, contributing to increasing the reputation of the new subdomain and injecting more credibility into its status.

Every new domain and mailbox always needs some warmup before it’s ready for action. No matter how long your main domain has been around and how good your current sender reputation is, it increases your chances of getting your emails delivered, but it doesn’t shield you from bad decisions. 

  • New SPF record and DMARC policy update. To fix the issue with the main SPF record, we generated a new one with our Folderly SPF Record Maker. With the help of this tool, we were able to include all email services The Client worked with. 

With this new record, we updated the DMARC policy for The Client, creating clear guidelines for processing messages that failed the authentication check. 


“Just when we thought that there was no way out of this situation, the Folderly team came to the rescue and put our campaigns back on track. Now it’s hard to believe that we were struggling months ago.”

  • Visible transactional emails. After several months of subdomain warmup, users started seeing trigger emails in their inboxes upon interacting with the online store. The emails arrive as soon as the website confirms the visitor’s target action without any delays or conflicts with the recipients’ spam filters.
  • Conversion and engagement boost. With transactional emails no longer disappearing into the void, more users got converted into buyers, allowing The Client to see an increase in revenue and website traffic and discover more remarketing opportunities for the users who didn’t complete a purchase or decided to wait for a certain product.

  • Increased open rate. After dividing marketing emails and transactional emails into two separate channels and fixing DNS records for the main domain and subdomain, we saw a positive dynamic for the main domain’s open rate, which went from 5%-10% to a healthy 30%.

This result demonstrated that marketing emails, too, were affected by sharing a domain with transactional emails due to the inability to work out a steady schedule and build a pace that would contribute to creating a solid sender reputation and gain more trust from internet service providers. With this problem out of the way, The Client was able to unleash the full potential of the marketing campaigns.

Key takeaways

  • Take your transactional emails seriously. If you work in e-commerce or retail and have an online store in addition to the physical one, transactional emails are your bread and butter. The faster they arrive to the user’s inbox, the more the user is inclined to complete the purchase and return to your online store. Trigger emails demonstrate your readiness to interact with your target audience, address their needs and provide them with high-quality service. This is the foundation for your customers’ trust.  No amount of flashy marketing emails and funny social media posts can make up for transactional email issues. 
  • Treat your subdomain as your main domain. When you create a subdomain, it doesn’t matter if it’s related to your main domain. From the perspective of internet service providers, it’s still a new domain, its behavior patterns are unknown. You must introduce it gradually, warming it up, generating DNS records and monitoring your progress.
  • Check your DNS records. It’s okay to feel confused about your DNS records. But don’t let that confusion affect your email marketing. There are many tools that let you check and adjust your SPF record whenever you add a new service or mechanism. If you decide to leave everything to chance, chances are you’ll compromise your DMARC policy and your relationship with spam filters and email service providers.  
  • Remember that deliverability tools are good for B2C, too. You may be working with a more responsive and eager audience compared to B2B prospects. However, it doesn’t mean that you’re safe from deliverability issues or that your domain can’t get blacklisted. Just like all businesses that use email marketing for sales, you need a clear view of your mailboxes and a good understanding of what’s going on every time you hit “Send.” So, don’t forget to add a user-friendly tool to your arsenal of email marketing platforms. 
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