Common Reasons Emails are Flagged as Spam


In Gymini, ensuring that your gym's marketing emails reach your subscribers' inboxes is crucial. However, there are instances when emails might be flagged as spam by mailbox providers. Understanding these reasons and implementing solutions can significantly improve your email deliverability.


Mailbox providers employ various algorithms and checks to protect their users from unwanted or potentially harmful emails. Here are the most common reasons emails might be flagged as spam and how you can address them:

1. Sending From a Public Domain

Issue: Sending emails from free domains like or can raise red flags for spam filters.

Solution: Always send emails from a domain that you own, ensuring it aligns with your gym's branding.

2. DMARC Issues

Issue: If the sending domain has a DMARC policy but hasn't been verified with your SMTP provider, emails might be flagged as spam.

Solution: Verify your domain with your SMTP provider to ensure your emails pass DMARC checks. Consult your SMTP provider for detailed instructions.

3. List Health & Collection Practices

Issue: The health of your email list and how you collect subscribers play a significant role in deliverability.


  • Ensure every subscriber has given explicit consent to receive emails from your gym.

  • Regularly clean your list to remove cold or unengaged subscribers.

  • Secure your subscription forms with a double opt-in to prevent unwanted sign-ups.

For a deeper dive into deliverability factors, refer to our "Introduction To Email Deliverability" article.

4. Sending Internal Mail

Issue: Sending emails within the same domain (e.g., from to can result in them being flagged as spam. This happens because the receiving mailbox detects an email from its own domain that it didn't send, leading it to suspect spoofing.


  • For testing purposes, use a different email domain, such as a free address.

  • If you need to send internal emails outside of testing, ask your domain's mail manager to whitelist the IP address of your SMTP provider.


Ensuring your emails reach your subscribers' inboxes is paramount for effective communication and marketing in Gymini. By understanding the common reasons emails are flagged as spam and implementing the provided solutions, you can optimize your email deliverability, ensuring your gym's messages are seen and engaged with by your subscribers.

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