Email marketing has established itself as the essential communication and promotional channel for advertisers, regardless of their sector. Whether for informing, building loyalty, or acquiring new customers, email remains the most ROI-effective lever for a brand.
But for this lever to be as effective as possible, it is crucial that emails sent by a brand arrive in the inbox… Email deliverability has therefore become a major challenge for marketing and communication departments.
A drop in deliverability can have significant impacts on your business. Fewer messages arriving in inboxes mean poorer coverage of your communications, but more importantly, fewer messages read and clicked, ultimately leading to fewer conversions and potentially less leads or revenue.

This article will guide you step-by-step through diagnosing and resolving these deliverability issues.,
even if you are not a technical expert.

1. Diagnose a deliverability issue

One of the key points in this continuous optimisation of your deliverability is the ability to quickly isolate an incident. Here are a few tips to help you identify any potential anomalies in a few steps.

1.1. Identify the signs of a problem

The first step is to identify the signals that indicate a deliverability issue. To do this, we advise you to focus on the following indicators

• An unusual drop in your open rates. For an equivalent target audience and equivalent theme, a significant variation in your rates should be a red flag. The exception to this is during holiday periods or intensive communication periods like Black Friday.
• An increase in undelivered emails (bounces), whether temporary (soft bounces) or permanent (hard bounces). Monitor your bounces over the long term. A significant rate of "address not found" (NPAI) soft bounces can indicate a deliverability issue on a particular campaign or a reputation problem.
• Unusually long delivery times for your emails. This indicator is more complex to monitor and analyse, but a drop in your reputation will, through a snowball effect, lead to increased reception times in the user's inbox.
• An increase in your messages being reported as unwanted by your recipients. The complaint rate is an increasingly monitored indicator by webmail providers and ISPs. Beyond a certain rate or number of complaints, sanctions will be imposed! Keep an eye on your rate.
  complaint. More details can be found in our article

 

1.2. Isolate the relevant webmails / ISPs

Once the anomaly is identified, you will be able to move on to the second stage of your audit and precisely target the problem. It is rare for a deliverability problem to occur across a range of webmails or ISPs at the same time. You will therefore need to isolate those experiencing the problem.
deliverability there is and for that:

• Examine email open rates by email provider to identify those performing below average.
• Please provide a comparison of the average open rates on your latest campaigns for each domain.
• Study the soft bounce error messages received in detail, based on the relevant domains

1.3. Assess the sender's reputation change

One of the solutions to deliverability problems is often found in analysing your sender reputation. To assess it:

• Use specialised tools like Sender Score or Google Postmaster Tools to track your domain and IP reputation
• Regularly check if you are on any blacklists using tools like MxToolbox.
• Identify the precise moment your reputation began to decline to understand the cause.

 

2. Identify the sources of the problem

It is now certain that you have a deliverability problem. Once diagnosed, it is important to identify what led to this degradation. We offer you some tips to identify the origin of your problems.

2.1. Analysis of KPIs from recent campaigns

The first step is to understand when your shipments faltered and to reconstruct the timeline of incidents. For this, the main indicators to monitor are:

• The drop in engagement rates (opens and clicks)
• Increase in invalid addresses (NPAI Hard)
• The rise in spam complaints
• The raising of addresses of the «spam trap» type (spam trap email boxes from webmails or ISPs to identify potential spammers)
• The increase in cancellation requests

2.2. Analysis of the database quality

Basic quality issues are very often at the root of a deliverability problem. A new imported list, sending to inactive recipients, etc. – identify what could have caused the problem:

• The percentage of valid addresses in your database: if it has fallen, that is a good indicator.
• The active contact rate: this corresponds to your contacts who have been contacted by email and who have opened at least one campaign. This indicator should be monitored over time to identify a drop in this rate and the actions to be implemented.
• The quality of recent imports and new contacts: have you launched an acquisition campaign or imported contacts without testing them beforehand? You might be on the right track.
• The reliability of data from external sources (CRM, other tools): You are uncertain about the quality of the data present in tools within your information system that exchange contacts with your marketing emailing campaign routing solution; an audit of the addresses present could be a good solution.
• The origin of problematic contacts (file rentals, imports, competitions): If you have an aggressive contact acquisition policy, it's possible that quantity comes at the expense of quality.

2.3. Technical configuration analysis

At first glance, this section might appear more complex for individuals without a technical background, but rest assured, there are websites that allow you to perform a diagnosis in just a few clicks. We recommend prioritising the validation of:

• The correct configuration of SPF, DKIM, and DMARC records: you can use the following website: mxtoolbox.com
• The health of your IP reputation and domain: we advise you to use the following sites for this: senderscore.org you Postmaster (Google Postmaster Tool) or spamhaus.org

2.4. Structure and content of emails

It is possible that your deliverability issue is temporary and due to the message you routed. Indeed, your message (from the subject to the content of your email) may be considered spam by webmail providers or ISPs:

• Code elements can increase your spam score
• Certains contenus en particulier sont susceptibles d’être considérés comme indésirables (mot clé par exemple)
• Poor adherence to good practices can also have an impact (e.g. text/image ratio too low, quality of links or URLs in a link, etc.)

If you have identified a problematic email or if you wish to ensure the quality of your email before sending it, the website Mail Tester  will give you good indications.

2.5. Verification of Marketing Programmes

The analysis of messages you send as part of newsletters should be studied closely, but not only that... Indeed, if you have deployed a relational programme with automated email campaigns, you must also dig in that direction:

• Analyse the new automatic email scenarios that have recently been put in place
• Validate the relevance of your campaigns' content and targeting
• Monitor for unusual variations in sending volume: webmail providers and ISPs do not like unusual spikes in activity which may be explained on your end... but not on theirs!

3. Action plan to restore the situation

You have been able to identify a deliverability issue and understand its source, it is now time to implement corrective actions to allow you to return to normal. We advise you to follow the following steps:

3.1. Clean and optimise your contact database

The priority actions to be carried out are the following:

• Remove all invalid email addresses from your database
• Check your entire database for any unrecognised hard N.P.A.I.s.
• Ensure complaints and unsubscribes are handled correctly.

3.2. Targeting assets and isolating liabilities

For a time, you will need to trim your sails and route your campaigns within a more restricted circle of contacts:

• Identify the dormant assets (6, 12, and 18 months) for the problematic domains and quarantine them.
• Stop sending to inactive users for more than 6-12 months: ideally, plan a reactivation scenario for inactive users and deal with them if they don’t open or click your email to put them in quarantine or ideally delete them.
• Focus your mailings on your most engaged contacts: for this, solutions like Smartprofile offer an engagement score for email channels. Use this type of score to only send to your most responsive contacts.

3.3. Reinforcing technical aspects

Don't overlook the technical aspects and focus on the following essential points:

• Check and correct SPF, DKIM, and DMARC configurations if necessary
• Implement an appropriate DMARC policy (quarantine or reject)

3.4. Working on email content

Implement a continuous improvement process that takes into account best practices
following:

• Personalise the content according to your segments
• Optimise the content to avoid spam filters
• Create clear and engaging CTAs
• Make unsubscribing easier
• Test your emails on different platforms

3.5. Manage the transition period.

You will need to be patient as a degraded reputation from a few shipments can take several weeks to return to its pre-crisis level… We advise you to take the following actions during your transition period:

• Consider a transition to a dedicated IP with a «warming-up» phase»
• Reduce shipment volumes and spread them out over time
• Launch targeted reactivation campaigns
• Set up regular automatic emails (birthdays, etc.) to have a recurring volume of emails routed across all webmails and ISPs.
• Test different parameters (times, objects, content)
• Keep a close eye on your KPIs

Deliverability is a crucial element for the ROI of your email campaigns. To maintain good deliverability, keep these three essential steps in mind: diagnose regularly, maintain a clean database, and continuously optimise your practices. The use of a solution
Emailing supported by a deliverability team like Smartprofile's will greatly facilitate these steps.

And our final recommendations: don't forget to implement a double opt-in for your new subscribers, and always begin the relationship with a welcome email to engage your contacts from the outset!