1. Introduction
2. Possible Reasons for Google Email Sending Restrictions
3. Verify your SPF, DKIM & DMARC setup
4. Ensure that your emails have unsubscribe link
5. Set up valid reverse DNS records of your IP addresses
6. Tweak your email campaigns
7. Monitor your bounce list
8. More information

Introduction

The algorithm that Google uses to determine whether or not an email goes to spam is a black box. There’s no definitive way to understand how it truly works. However, there are certainly tips and tricks you can utilize to minimize the chances of your email being marked as spam.

Possible Reasons for Google Email Sending Restrictions

Before we delve into various tips, let’s first examine the reasons why Google might block your account from sending emails:

1. Excessive hard bounces
2. The Gmail account is relatively new
3. Absence of an unsubscribe link
4. High number of recipients marking emails as spam
5. Content flagged as spam

Verify your SPF, DKIM & DMARC setup

If you are using Google Workspace, it is imperative to set up your SPF, DKIM, and DMARC correctly. SPF, DKIM, and DMARC are technologies designed to prevent spam, spoofing, and phishing through Gmail authentication.

1. Ensure mail delivery & prevent spoofing with SPF. Instructions are here.
2. Increase security for outgoing emails with DKIM. Instructions are here.
3. Enhance security for forged spam with DMARC. Instructions are here.
4. Add your brand logo to DMARC-authenticated messages. Instructions are here.

Google provides a helpful tool to check this. Simply visit: https://toolbox.googleapps.com/apps/checkmx/check and enter your domain name to verify all your domains.

If everything is correctly set up, you will receive all green checkmarks.

Another tool to check your MX, DKIM, and DMARC settings is MXToolBox SuperTool.

For more details on how to set this up, please refer to the Google Workspace support page: https://support.google.com/a/answer/10583557?hl=en&ref_topic=9061731

Ensure that your emails have unsubscribe link

Unsubscribing from unwanted emails should be easy and require just one click. Not providing an unsubscribe link also violates FTC regulations and Google’s guidelines. For more information on compliance, visit the FTC’s guide at https://www.ftc.gov/business-guidance/resources/can-spam-act-compliance-guide-business
Google support note that subject is at https://blog.google/products/gmail/gmail-security-authentication-spam-protection/

For steps on adding an unsubscribe link to your emails, refer to the guide Adding an Unsubscribe Link to MailKing or Gmail Auto Follow Up Campaigns.

Set up valid reverse DNS records of your IP addresses

In addition, you should set up valid reverse DNS records for your IP addresses that point to your domain. If your domain does not have a website, create one with Google or similar providers.
Also, maintain updated contact information in your WHOIS record and on abuse.net.

Tweak your email campaigns

If your emails are still landing in spam or being blocked, try the following:

1. Ensure that your email addresses are real. Validate all your email addresses – sending emails to purchased email address lists is particularly risky.
2. Ensure that all your campaigns include an unsubscribe link. Instructions on how to add one are here.
3. Recipients can easily mark your email as “Not Safe” or spam to avoid seeing your messages. Include clear instructions for recipients to mark your emails as Safe. This helps in avoiding blacklisting and bounced messages.
4. Try sending an email campaign without “link tracking”. To disable link tracking, uncheck the option Enable link tracking in the campaign window. Check for links. Google might think that your email may include links to unsafe content.
   • Replace all HTTP links with HTTPS.
   • Remove links to public Google Documents.
   • Do not use public URL shorteners like bit.ly.
   • If you are sending links, try to send links pointing to the domain that is sending emails. For instance, if you are sending from support@acme.com, then your links should point to https://www.acme.com.
5. Don’t send emails with various contents all in the same email. If you are sending an email with promotional content, don’t include purchase links.
6. Ensure that there are no typos so that Gmail doesn’t categorize them as spam.
7. Use more text instead of images, as the latter is often associated with spam.
8. Messages of the same category should have the same email address in the From: header. For example, messages from a domain called solarmora.com might have From: headers like this:
   • Purchase receipt messages: receipt@solarmora.com
   • Promotional messages: deals@solarmora.com
   • Account notification messages: alert@solarmora.com
9. Check your emails (both body and signature) for spammy contents. Although unintentional, your email may include phrases historically used by known spammers. As a general guideline, avoid the following:
   • Lots of exclamation marks
   • “Must read”
   • Bitcoin or cryptocurrency keywords
   • Attention-getting claims (free money, etc.)
   • Large and/or gaudy colored text
   • Text the same color as the background
   • Tiny text
   • (Almost) zero height images
   • Links hidden under text
   • Images or links with a different URL
   • Avoid using mailto: links
10. Google’s algorithms can be quite strict for new accounts. Account tenure is a factor for email sending limits. Generally, Google Workspace accounts with at least six billing cycles with Google are considered seasoned and can enjoy sending up to 1,500 daily emails. Accounts with fewer than six billing cycles face much stricter spam rules.

Monitor your bounce list

As a rule of thumb, you should aim for a bounce rate below 3 percent. Google will penalize your sender reputation if your bounce rate exceeds 3 percent, impairing your ability to send campaigns effectively.

MailKing will automatically detect bounces. You can also use Export Emails to Google Sheets, which includes an Email Bounce Checker. This export will automatically create a spreadsheet for you, neatly organizing every bounced email you’ve ever encountered.

More information

1. FTC CAN-SPAM Act: https://www.ftc.gov/business-guidance/resources/can-spam-act-compliance-guide-business
2. Google blog post on bulk sending: https://blog.google/products/gmail/gmail-security-authentication-spam-protection/
3. Google sending guidelines: https://support.google.com/mail/answer/81126
4. Google sending limits: https://support.google.com/a/answer/166852?hl=en
5. Restore a suspended Gmail account: https://support.google.com/a/answer/2789146