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15 Reasons Why Your Emails May Not Be Delivered to Gmail Recipients

If you are a bulk email sender, meaning you send close to 5,000 messages or more to personal Gmail accounts within a 24-hour period, you need to follow Google's email sender guidelines to ensure your emails are delivered as expected. Failing to meet these guidelines may result in Google limiting your sending rates, blocking your messages, or marking them as spam. Here are 15 possible reasons why your emails may not be delivered to Gmail recipients, based on the limits, filters and guidelines published by Google.

Table of Contents:

- Introduction

- Reason 1: You have not set up SPF and DKIM for each domain that sends mail

- Reason 2: You are not sending with an aligned `From` domain in either the SPF or DKIM domains

- Reason 3: You have not set up DMARC for each domain that sends mail

- Reason 4: You have not configured your DMARC policy to `p=reject` or `p=quarantine`

- Reason 5: You have not registered your sending domains with Postmaster Tools

- Reason 6: You have a high spam rate or a low reputation score on Postmaster Tools

- Reason 7: You are sending unwanted or unsolicited emails to Gmail recipients

- Reason 8: You are not making it easy for Gmail recipients to unsubscribe from your emails

- Reason 9: You are not following the best practices for email design and content

- Reason 10: You are not following the best practices for email list management

- Reason 11: You are not following the best practices for email sending frequency and timing

- Reason 12: You are not following the best practices for email deliverability testing and monitoring

- Reason 13: You are not complying with the laws and regulations that apply to your email marketing activities

- Reason 14: You are not respecting Gmail's limits for sending mail

- Reason 15: You are not aware of Gmail's changes or updates that may affect your email deliverability

- Conclusion

- Sources

Reason 1: You have not set up SPF and DKIM for each domain that sends mail

SPF and DKIM are two email security protocols that validate the sender's IP address and ensure the integrity of the message. They also prevent your domain from being impersonated by spammers or phishers. Google requires bulk email senders to set up SPF and DKIM records for each domain that sends mail and add them to their DNS or the platform that hosts SPF and DKIM for their domain. Starting from February 2024, Google will gradually enforce this requirement with error codes on non-compliant email traffic, and from April 2024, it will increase the rejection rate for non-compliant email traffic.

Reason 2: You are not sending with an aligned `From` domain in either the SPF or DKIM domains

This means that the sender's domain specified in the `From` address does not match the domains authorized by SPF records and covered by DKIM signatures, respectively. Google and Yahoo (which has similar requirements for bulk email senders) require either SPF or DKIM alignment to verify the sender's identity and prevent spoofing.

Reason 3: You have not set up DMARC for each domain that sends mail

DMARC is another email security protocol that builds on SPF and DKIM and allows you to specify how receivers should handle unauthenticated or unaligned messages from your domain. It also provides you with reports on your email authentication performance and potential issues. Google requires bulk email senders to set up DMARC records for each domain that sends mail and publish them in their DNS or the platform that hosts DMARC for their domain. Starting from February 2024, Google will gradually enforce this requirement with error codes on non-compliant email traffic, and from April 2024, it will increase the rejection rate for non-compliant email traffic.

Reason 4: You have not configured your DMARC policy to `p=reject` or `p=quarantine`

These are two possible values for the DMARC policy that tell receivers what to do with unauthenticated or unaligned messages from your domain. `p=reject` means that such messages should be rejected outright, while `p=quarantine` means that they should be marked as spam or placed in a separate folder. Google requires bulk email senders to configure their DMARC policy to either `p=reject` or `p=quarantine` to prevent malicious actors from abusing their domain and harming their reputation. Starting from February 2024, Google will gradually enforce this requirement with error codes on non-compliant email traffic, and from April 2024, it will increase the rejection rate for non-compliant email traffic.

Reason 5: You have not registered your sending domains with Postmaster Tools

Postmaster Tools is a free service provided by Google that allows you to monitor your email delivery performance, troubleshoot issues, and optimize your email practices. By registering your sending domains with Postmaster Tools, you can access valuable data such as spam rate, delivery errors, authentication results, feedback loop reports, and more. This can help you identify and resolve any problems that may affect your email deliverability to Gmail recipients.

Reason 6: You have a high spam rate or a low reputation score on Postmaster Tools

Spam rate is the percentage of messages sent from your domain that Gmail users mark as spam, while reputation score is a measure of how Gmail users perceive messages from your domain based on various factors such as engagement, complaints, bounce rate, etc. If you have a high spam rate or a low reputation score on Postmaster Tools, this indicates that your emails are not relevant, wanted, or trustworthy by Gmail recipients, and Google may limit your sending rates, block your messages, or mark them as spam.

Reason 7: You are sending unwanted or unsolicited emails to Gmail recipients

Unwanted or unsolicited emails are those that Gmail recipients did not explicitly request or consent to receive from you, such as promotional offers, newsletters, surveys, etc. Sending unwanted or unsolicited emails to Gmail recipients violates Google's email sender guidelines and may result in your messages being marked as spam or blocked by Gmail filters.

Reason 8: You are not making it easy for Gmail recipients to unsubscribe from your emails

If you are sending promotional or commercial emails to Gmail recipients, you must provide them with a clear and conspicuous way to opt out of receiving future emails from you, such as a link or a button in the email footer. You must also honor their unsubscribe requests promptly and without requiring them to provide any additional information or take any further steps. Failing to do so may result in your messages being marked as spam or blocked by Gmail filters.

Reason 9: You are not following the best practices for email design and content

The design and content of your emails can affect how Gmail recipients perceive and interact with your messages, and how Gmail filters classify them. Some of the best practices for email design and content include using a clear and descriptive subject line, avoiding excessive use of images, links, or attachments, using plain text or HTML format instead of rich media or JavaScript, avoiding spammy words or phrases, personalizing your emails, and providing relevant and useful information.

Reason 10: You are not following the best practices for email list management

The quality and hygiene of your email list can affect your email deliverability to Gmail recipients, as well as your reputation and sender score on Postmaster Tools. Some of the best practices for email list management include obtaining explicit permission from your subscribers before sending them emails, segmenting your list based on their preferences and behavior, removing inactive or unengaged subscribers, validating your email addresses regularly, and avoiding purchasing or renting email lists from third parties.

Reason 11: You are not following the best practices for email sending frequency and timing

The frequency and timing of your emails can affect how Gmail recipients respond to your messages, and how Gmail filters handle them. Some of the best practices for email sending frequency and timing include sending emails at optimal times based on your subscribers' location, activity, and preferences, avoiding sending too many or too few emails, testing different frequencies and timings to find the best ones for your audience, and respecting your subscribers' expectations and preferences.

Reason 12: You are not following the best practices for email deliverability testing and monitoring

Testing and monitoring your email deliverability can help you identify and fix any issues that may prevent your emails from reaching Gmail recipients' inboxes, such as authentication errors, spam complaints, delivery errors, etc. Some of the best practices for email deliverability testing and monitoring include using tools such as Postmaster Tools, DMARC reports, spam checkers, inbox placement tests, etc., analyzing the results and metrics of your email campaigns, such as open rate, click rate, bounce rate, etc., and making adjustments and improvements based on the feedback and data.

Reason 13: You are not complying with the laws and regulations that apply to your email marketing activities

Depending on where you operate and where your subscribers are located, there may be different laws and regulations that govern your email marketing activities, such as the CAN-SPAM Act in the US, the GDPR in the EU, the CASL in Canada, etc. These laws and regulations may have different requirements for obtaining consent, providing unsubscribe options, disclosing your identity and contact information, etc. Failing to comply with these laws and regulations may result in legal penalties or fines, as well as damage to your reputation and deliverability.

Reason 14: You are not respecting Gmail's limits for sending mail

You are not respecting Gmail's limits for sending mail. Gmail has limits for sending mail to prevent abuse and ensure a good user experience. These limits apply to both personal Gmail accounts and Google Workspace accounts that send mail to personal Gmail accounts. Some of these limits include 500 recipients per message (or 2000 if you use Google Workspace), 500 unique recipients per day (or 10,000 if you use Google Workspace), 100 total recipients per 10-minute period (or 3000 if you use Google Workspace), etc. Exceeding these limits may result in temporary errors or permanent failures when sending mail.

Reason 15: You are not aware of Gmail's changes or updates that may affect your email deliverability.

Gmail is constantly evolving and improving its features and functionality to provide a better user experience and a safer inbox. As a bulk email sender, you need to stay updated on Gmail's changes or updates that may affect your email deliverability to Gmail recipients, such as new policies, requirements, filters, algorithms, etc., and adapt your email practices accordingly.

Sources:

- Email sender guidelines - Google Workspace Admin Help

- Email sender guidelines FAQ - Google Workspace Admin Help