Email support: SPF, DKIM, DMARC and Joomla

Do your emails not arrive, do messages disappear into the spam folder, or do Gmail, Outlook and Hotmail reject your email? db8 helps you find and fix email problems.

From SMTP settings and Joomla contact forms to SPF, DKIM and DMARC. This way you improve the reliability and deliverability of your business email.

Email problems? We find out where it goes wrong

A quote that does not arrive, a customer who gets no confirmation, or a contact form that does not send email: email problems can have a direct effect on your business. Often everything looks correctly set up, while a mail server rejects messages or puts them in the spam folder.

Email passes through several systems: your website or email program, a sending mail server, DNS settings and the receiving mail server. One error in one part can be enough to break the delivery.

At db8 we find the technical cause. We check the settings, analyse error messages and test if the receiving mail server really accepts the messages.

How can we help you?

• Email is not received: find out why messages do not arrive or are rejected.
• Email ends up in spam: check authentication, mail server settings and possible reputation problems.
• SPF, DKIM and DMARC: check, set up and improve email authentication via DNS.
• SMTP problems: fix connection errors, authentication errors and wrong sending settings.
• Joomla email problems: repair email from contact forms, registrations, password resets and extensions.
• Outlook, Hotmail and Gmail: find out why large email providers reject your messages.
• DNS and mail servers: check MX records, reverse DNS and relevant server configurations.
• Email templates: improve automatic Joomla messages, sender details and HTML layout.

SPF, DKIM and DMARC: the basis for reliable email

Email providers check more and more strictly if messages come from a trusted sender. That is why three techniques are important for the security and deliverability of your email.

SPF: which mail servers may send on your behalf?

SPF (Sender Policy Framework) is a DNS record that tells which mail servers may send email on behalf of your domain. A wrong SPF record can cause legitimate messages to be rejected.

Do you use several sending services, for example Microsoft 365, a website and a newsletter system? Then the relevant senders must be included correctly in your SPF configuration.

DKIM: a digital signature for your messages

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outgoing email. With it, the receiving mail server can check if the message was signed with the correct key and was not changed on the way.

A missing or invalid DKIM signature can have a negative effect on how your messages are judged.

DMARC: protect your domain name against abuse

DMARC (Domain-based Message Authentication, Reporting and Conformance) builds on SPF and DKIM. It checks if the authenticated domain name matches the visible sender, and it gives receiving servers a policy for messages that fail this check.

DMARC helps to fight domain spoofing and, through reports, gives insight into the systems that send email on behalf of your domain.

A DMARC record alone is not enough: the SPF or DKIM authentication behind it, and the domain alignment that goes with it, must also be correct. We check these parts together and advise on a safe introduction of the DMARC policy.

Want to know more? Read our article Optimise the delivery of your emails.

Outlook and Hotmail reject your email?

Microsoft and Google use stricter and stricter rules for email authentication. Since November 2026 there are also reports of Outlook.com and Hotmail rejecting messages from smaller senders when a DMARC record is missing.

A possible error message is:

550 5.7.1 Message rejected: Message lacks SPF/DKIM/DMARC Auth Records

This message can mean that your domain is not configured well enough for the authentication checks of Microsoft. Even when SPF and DKIM are present, a missing DMARC record can cause problems.

db8 checks the DNS records, looks into the error message and helps you apply the correct settings. We also look at other sending services that use your domain name, so existing email flows are not blocked by accident.

Read also: Outlook and Hotmail reject email without DMARC: this is how you fix it.

Joomla does not send email? We help

A Joomla website sends several kinds of automatic messages, such as contact form notifications, registration confirmations, password resets and notifications. When these emails do not arrive, the problem is not always in the form itself.

db8 has specialist knowledge of Joomla, PHP and Linux mail servers. Among other things, we look at:

• The email settings in the Joomla Global Configuration.
• The choice between PHP Mail, Sendmail and SMTP.
• SMTP authentication, encryption and connections to the mail server.
• Sender addresses, Reply-To settings and domain authentication.
• Joomla extensions that use their own email settings.
• Mail templates for system notifications and automatic messages.
• Error messages, email headers and server logs.

We test step by step if Joomla can send a message, if the extension in use works correctly, and if the receiving mail server accepts the message. This way we deal with the cause, instead of changing settings at random.

You can find more technical background in the articles Joomla email settings and Solving Joomla email problems.

How does our email support work?

1. Map the problem. We discuss which messages do not arrive, which systems you use and which error messages you get.
2. Technical analysis. We check relevant DNS records, mail server settings, email headers and, where possible, the server logs.
3. Fix the problem. We repair wrong settings, or advise which changes are needed at your hosting or email provider.
4. Test the sending. We check that it works with test messages and review the results of the email authentication.
5. Advice for the future. You get an explanation of the cause and recommendations to help prevent similar problems.

A successful SMTP delivery does not automatically mean that a message lands in the inbox. That is why we make a difference between sending, accepting and really delivering email.

Why email support from db8?

At db8 we combine knowledge of websites, Joomla, PHP, Linux, DNS and mail servers. Because of that, we look further than only the settings of your email program. We look at the complete technical route that a message takes.

Peter Martin, Joomla specialist and Linux administrator, shares his technical knowledge about email configuration, deliverability, problem diagnosis and Joomla mail templates. We use this expertise to look into email problems in a systematic way.

Our approach is practical: first find out where it goes wrong, then fix it in a targeted way, and then test it. Without unnecessary changes to systems that already work well.

Need help with your email problems?

Are your emails rejected, do important messages not arrive, or do you want to check if SPF, DKIM and DMARC are set up correctly? db8 is happy to help you with a technical analysis and a targeted solution.

Contact db8 for email support. If possible, mention your domain name, the email provider you use and any error messages. This helps us find the problem faster.

Contact us for email support