Deliverability refers to whether your emails actually arrive in your guests' inboxes, not just whether they were sent. An email can leave SHR CRM and still fail to reach a guest if it is flagged by spam filters, blocked during content screening, or routed to the spam folder by the receiving mailbox provider.

This article explains how SHR CRM handles delivery, what affects whether your emails reach guests, and what steps you can take if emails are not arriving.

SHR CRM uses Amazon Simple Email Service (SES) to send all marketing and transactional emails. Amazon SES is an enterprise-grade delivery platform that monitors sender reputation, meaning how trusted your emails are by receiving providers like Gmail, Outlook.com, and Yahoo.

As part of this integration, emails are subject to content screening before they are dispatched. The content of your email is evaluated against spam and abuse signals before it leaves the platform. If an email fails those checks, it is suppressed and will not be sent.

Image-only emails are the most common cause of delivery failure. An email that contains only images and no readable text is a well-known spam signal. Spam filters have no text to analyse, which makes the message appear suspicious. A marketing email built as a single image, even a beautifully designed one, is likely to be blocked or routed to spam.

Every email must contain meaningful readable text. A common starting guideline is a 60:40 split: 60% text, 40% images. and this is still widely cited as a reasonable benchmark. More precisely, research from Email on Acid found that emails containing at least 500 characters of readable text pass content filters consistently regardless of image count. The core principle is that your email must communicate its message in text alone, even if images are blocked. Spam filters cannot read images, and neither can recipients using screen readers.

Keep your total email file size under 100KB. Testing by Email on Acid found that emails above 100KB in total file size begin failing against multiple spam filters. You can check your email's file size using a pre-send testing tool such as Email on Acid or Litmus before sending.

When building emails using SHR CRM's native templates and designer, the system manages the underlying code structure for you, this is handled automatically. However, if you upload your own HTML template, code quality becomes your responsibility. Unnecessary code, duplicated styles, and non-standard structures all increase file size and can trigger spam filters. Images are typically not the cause of file size issues here, it is the quality of the code itself that matters.

Emails should be sent in multipart format, meaning they include both an HTML version and a plain-text fallback. Some spam filters flag HTML-only messages. SHR CRM's built-in email builder automatically includes a plain-text version alongside HTML content.

Certain words and formatting patterns in subject lines and body copy increase spam scoring. Common triggers include:

Your "From" name and email address should be recognisable and match what guests expect from your property. Anti-spam regulations also require marketing emails to include a physical mailing address. SHR CRM includes fields for this information during email setup.

SHR CRM supports uploading custom HTML templates. However, we cannot guarantee that custom HTML meets the content standards required for delivery through our Amazon SES integration.

Custom HTML submissions frequently contain patterns that trigger content filtering:

In testing, emails built using the SHR CRM drag-and-drop builder consistently pass content checks and deliver successfully. Custom HTML that does not meet modern email standards may be suppressed, even if no error is displayed.

Email authentication is now a hard requirement for inbox placement with major providers. In 2024, Google and Yahoo both mandated that bulk senders have SPF, DKIM, and DMARC records configured correctly. Without them, your emails are more likely to be rejected or marked as spam, even if the content is perfectly clean.

Here is what each record does:

SHR CRM's Amazon SES integration requires these records to be configured in your domain's DNS settings. Your IT team or domain administrator is responsible for these settings.

SHR CRM automatically manages hard bounces for you. When an email is sent to an address that no longer exists, this is recorded as a hard bounce. SHR CRM automatically adds hard-bounced addresses to the global Do Not Contact list, so they are removed from all future sends without any action required from you. This protects your sender reputation by preventing repeated sends to invalid addresses.

SHR CRM automatically includes unsubscribe links in marketing emails. Do not attempt to remove these. Recipients must be able to opt out, and failing to honour unsubscribes is both a legal requirement under global spam and data protection regulations and a practical deliverability risk, guests who cannot unsubscribe mark emails as spam instead, which damages your sender reputation far more than an unsubscribe would.

Investing in a dedicated email testing tool is one of the most effective steps you can take to protect deliverability and ensure your emails render correctly before they reach guests.

Two widely used industry tools are Email on Acid and Litmus. Both allow you to:

These tools are particularly valuable if you are sending high volumes, running campaigns to international audiences, or working with custom-designed email templates. They give you confidence in what you are sending before it reaches any guest's inbox.

Both Email on Acid and Litmus offer free trials. Your SHR Customer Success contact can advise on which may suit your team's needs.

If a campaign shows unexpectedly low delivery, or test emails are not arriving, work through these steps in order.