Booking emails are landing in spam: what should I do?

Authenticate your domain (SPF, DKIM, DMARC), send via SMTP from your own domain and meet the Gmail and Yahoo requirements in force since 2024.

If your booking confirmations land in spam, it is most often because your domain is not authenticated: mailbox providers cannot verify that the email really comes from you. The solution is to send via SMTP from an address on your own domain, then publish SPF, DKIM and DMARC records. Since February 2024, Gmail and Yahoo have required at least this kind of authentication from all senders. With GDA Kraft Booking, the plugin by Global Digital Agency, emails are sent through your WordPress site's sending system: that is what needs configuring.

Why are your emails classed as spam?

By default, WordPress sends its emails using the hosting server's mail function. The message often goes out from a generic address or a shared server that nothing links to your domain. To a mailbox provider, it then looks like spoofing.

Three mechanisms let you prove where a message comes from:

Mechanism	Definition	Where to configure it
SPF	Public list of the servers authorised to send for your domain	Domain's DNS zone
DKIM	Cryptographic signature added to each message, verifiable with a key published in DNS	Email provider, then DNS zone
DMARC	Rule saying what to do if SPF and DKIM fail, and checking that the visible sender domain is consistent (alignment)	Domain's DNS zone

Alignment means that the domain shown in the “From” field matches the domain validated by SPF or DKIM.

What do Gmail and Yahoo require?

According to Google's email sender guidelines (consulted on 12 October 2026), since 1 February 2024, all senders to personal Gmail accounts must in particular:

set up SPF or DKIM for their sending domain;
have a valid reverse DNS record (PTR) for the sending server;
use a TLS connection;
keep their reported spam rate below 0.3%, with Google recommending staying below 0.1%.

Senders of more than 5,000 messages a day must also set up SPF and DKIM, publish a DMARC record and offer one-click unsubscribe for marketing messages. Yahoo publishes comparable requirements on its Sender Hub (consulted on 12 October 2026).

Your booking emails are transactional messages sent in small volumes: the “all senders” requirements apply to you. Setting up DKIM and DMARC as well remains best practice.

How do I fix it, step by step?

Test sending from Kraft Booking › Settings, “Email design and content” section, with the “Save and send me a test” button (the email goes to your WordPress account's address: use a Gmail account, then another mailbox provider).
Choose a sender address on your own domain (for example bookings@your-domain.com), to be set in your SMTP plugin, never a personal Gmail or Outlook address: you cannot authenticate a domain you do not own.
Install an SMTP plugin and configure it with the credentials of your business mailbox or a transactional email service.
Publish SPF: your email provider gives the exact value to add to your DNS zone. A domain must have only one SPF record.
Enable DKIM with your email provider and publish the key it gives you.
Publish DMARC, starting with a monitoring policy, for example:

v=DMARC1; p=none; rua=mailto:dmarc@your-domain.com

The exact name of the record to create is given by your DNS host. Once the reports look good, you can tighten the policy.

Check the headers of an email received in Gmail (“Show original” option): SPF, DKIM and DMARC should show “PASS”.
Check the “06 History” tab of a booking record, which traces the emails sent for that booking; the “Resend guest email” button lets you send it again.

Can the content cause problems too?

Yes, more rarely. A few rules for email templates:

a clear subject line, without capitals or strings of exclamation marks;
real text rather than a single image;
links to your own domain;
no unnecessary attachments.

The texts are customised in Settings › “Email design and content” (a single text per email, with no per-language tab): see Customise booking emails and Multilingual sites. If emails are not being sent at all, the “Emails are not received” section of Troubleshooting applies. An email in spam can also make the guest miss a balance payment link: see Payment declined: what should I do?.

Frequently asked questions

Can I send my confirmations from a Gmail address?

It is not advisable: you cannot publish SPF, DKIM or DMARC for the gmail.com domain, and Gmail applies a strict policy to messages that spoof its domain. Use an address on your own domain.

Do Gmail's requirements apply to a small host?

Yes, for the baseline: since February 2024, all senders to Gmail must at least authenticate their domain with SPF or DKIM and follow the other basic rules. The stricter obligations apply to senders of more than 5,000 messages a day.

How long do DNS changes take to work?

DNS records take anywhere from a few minutes to a few hours to propagate, depending on your provider. Send another test after that time.

Where do I configure SPF, DKIM and DMARC?

In your domain name's DNS zone, with your registrar or host. Your email provider gives the exact values to publish.