Why email delivery fails

You send a quote, an invoice or a reply to an enquiry, and the customer says they never received it. Or your website sends a notification that nobody sees. Email problems are frustrating because they are invisible: you rarely see an error, the message just disappears or ends up in spam.

Three records that prove you are who you say you are

Mailbox providers check whether an email really comes from your domain. Three settings in your domain's DNS do most of this work:

• SPF lists the servers and services that are allowed to send email for your domain. A domain should have only one SPF record, and it must include every service that sends for you, such as your mail provider, your newsletter tool and your website.
• DKIM adds a digital signature to each message, so the receiver can check it was not altered and really came from you.
• DMARC tells receivers what to do when a message fails those checks, and sends you reports. Many people start with a monitoring-only policy and tighten it once everything legitimate passes.

Large mailbox providers increasingly expect senders to have these in place. Without them, genuine email is more likely to be treated as suspicious.

Website forms that send "from" your domain

A very common problem: the website sends notifications using a basic server mail function, with your own address in the "from" field. To the receiving server that looks like someone pretending to be you. The fix is to send through an authenticated mail account or a proper sending service, and to add it to your SPF record.

Sender reputation

Receivers remember how people react to your messages. If recipients mark them as spam, or you send to old addresses that bounce, your reputation drops and more messages get filtered. Keep lists clean, send only to people who expect to hear from you, and make unsubscribing easy.

The message itself

Content still matters. Messages that are all images, use misleading subject lines, hide the unsubscribe option or contain many links are filtered more often. Plain, honest messages with a clear sender name do best.

A quick checklist

1. Send a test message to a personal address at a major provider and check where it lands.
2. Look at the message headers or use a free checking tool to see whether SPF, DKIM and DMARC pass.
3. Make sure every service that sends email for you is covered by your SPF record.
4. Check that website forms send through an authenticated account.
5. Remove addresses that keep bouncing.

These settings are small, but a single mistake in a DNS record can send real email to spam for months. If you would like someone to check them for you, our remote IT support includes email and domain settings.