Numerous emails to Gmail are suddenly undeliverable - what is behind this?

Why are my emails rejected?

If Gmail or other providers reject emails, this is called a bounce. This bounce can have several reasons, but the problem is basically Google's strict checking of various protocols.

Here is an example of a failed delivery because the message did not pass Gmail's DKIM check:

This behaviour not only costs nerves but can also cause unnecessary costs. Because it doesn't matter whether it's marketing campaigns, customer support or general communication, e-mails are the preferred medium and an indispensable tool for your company.
What can you do if your e-mails are not delivered or even marked as spam?

To avoid such delivery errors and bounces (e.g. Undelivered Mail Returned to Sender) and to ensure that emails you send via your domain can successfully pass the spam filters of Google and other email providers, there are three helpful protocols: SPF, DKIM and DMARC.

What are SPF, DKIM, and DMARC?

SPF (Sender Policy Framework) is an authentication method designed to determine which mail servers are authorized to send emails on your behalf. It prevents spammers from exploiting your domain to send fraudulent emails.

DKIM (DomainKeys Identified Mail) is another authentication method that ensures the integrity of an email message. It uses a digital key linked to the email message to ensure it hasn't been altered during transmission.

DMARC (Domain-based Message Authentication, Reporting & Conformance) is a protocol that combines SPF and DKIM and provides additional guidelines for handling unauthenticated emails. It also offers reporting features that allow domain owners to receive feedback on the delivery of their emails.

Why are these protocols so important?

These three protocols are core elements of email authentication and play a crucial role in detecting and preventing spam and phishing attempts. As a result, they are closely tied to your domain's spam reputation and directly influence the likelihood of your emails being classified as spam or being rejected.

1. Protection against Phishing and Spoofing: Cybercriminals often use fake email addresses to send fraudulent emails. Implementing these protocols ensures that only legitimate emails from your domain are sent.
2. Improved Email Deliverability: Email Service Providers (ESPs) check these authentication protocols to determine if an email is legitimate. If your emails pass these checks, they are more likely to land in the recipient's inbox and not the spam folder.
3. Increased Transparency: With DMARC reports, you can see exactly who is sending emails on your behalf, whether they were successfully delivered, and if they were authenticated.
4. Avoiding Bounces: Emails flagged as spam or rejected for other reasons can lead to bounces. This can harm your domain's reputation and affect the deliverability of future emails.

Benefits

For businesses, the correct implementation of SPF, DKIM, and DMARC can mean the difference between the success and failure of an email campaign. Some of the advantages include:

• Increased Deliverability: Your marketing and transactional emails are more likely to reach your customers' inboxes.
• Protection of Brand Reputation: By preventing phishing attacks and ensuring that only legitimate emails from your domain are sent, you safeguard your brand's reputation.
• Enhanced Customer Trust: Customers are more inclined to respond to emails when they are confident they come from a legitimate source.
• Cost and Time Savings: Businesses can save money and time by reducing bounces and increasing deliverability.

Act Now to Improve Reputation

By implementing SPF, DKIM, and DMARC, businesses can not only enhance their email deliverability and spam reputation but also protect their brand, strengthen customer trust, and ultimately maximize their ROI.

If you need more information or assistance in implementing these protocols, take a look at our detailed article on the topic: SPF, DKIM, and DMARC: How to improve spam reputation and avoid Bounces.

Check your configuration

You can check which protocols and settings you need to adjust with these tools, for example:

1. https://mxtoolbox.com - DMARC Check Tool
2. https://mecsa.jrc.ec.europa.eu/de - Email Communications Security Assessment (MECSA)
3. https://www.learndmarc.com - DMARC, DKIM & SPF Test

Example of mxtoolbox.com - missing DMARC configuration

Implementing and adapting configurations

If you receive error messages during the check by the tools mentioned above, additional settings are probably necessary for the DNS records of your domain provider through which you manage your domain and send e-mails.

If you need support or more information on the implementation of these protocols, take a look at our detailed article on the topic: SPF, DKIM and DMARC: Improve spam reputation and avoid bounces ->.