550 5.7.1 [x.x.x.x x] Gmail has detected that this message is likely suspicious due to the very low reputation of the sending domain. To best protect

[Mail-ocv]

Hi all,
I'm currently running an email campaign, but a significant number of emails to Gmail users are being blocked with the following error:

550 5.7.1 [x.x.x.x x] Gmail has detected that this message is likely suspicious due to the very low reputation of the sending domain. To best protect our users from spam, the message has been blocked.​

This seems to be tied to my domain or IP's reputation. I've reviewed the message content and spam score, and everything looks clean.
I’d really appreciate any help or insights on how I can reduce or fix this issue.
My questions:

1. What are the most effective ways to improve domain/IP reputation with Gmail?
2. Is setting up SPF, DKIM, and DMARC enough — or is there more to do?
3. Should I consider switching IPs, or is warming up my domain a better long-term approach?

Thanks in advance for any suggestions or recommendations.

 

[Ariel-ActiveRevenue]

1. What are the most effective ways to improve domain/IP reputation with Gmail?
2. Is setting up SPF, DKIM, and DMARC enough — or is there more to do?
3. Should I consider switching IPs, or is warming up my domain a better long-term approach?

hey — definitely a frustrating issue, and sadly pretty common when Gmail flags a domain or IP with low reputation.
setting up SPF, DKIM, and DMARC is the bare minimum. If you haven’t done that yet, start there. But even with those in place, Gmail still weighs sender reputation heavily — which is built over time based on engagement (opens, clicks), bounce rates, complaint rates, and sending consistency.
here's what I would consider -
1- warm-up is essential, especially if the domain is new or hasn’t sent consistently. Start with small batches, focus on your most engaged lists, and gradually increase volume.
2 - if your IP is shared, the reputation damage may not even be your fault. A dedicated IP gives you more control but also more responsibility.
3 - use tools like Google Postmaster Tools — it’s free and shows Gmail-specific reputation data.
4 - don’t overlook list hygiene. Even a few bad addresses can tank deliverability fast.

if you're running affiliate campaigns and need to diversify outside of email while you work on fixing this, I work with ActiveRevenue — a self-serve DSP that lets you drive targeted push/pop/display traffic to your offers on CPC/CPM. Could help fill the gap while your domain/IP reputation recovers.
quick question — how old is the domain you're using for these sends, and are you on a dedicated or shared IP right now?

 

[T J Tutor]

What are the most effective ways to improve domain/IP reputation with Gmail?

Have you considered using a new domain?

Monitoring and maintaining Domain Authority and Domain Reputation is very important to prevent the very issue you have now. Also, using a reputable email processor is a practical option to implement.

Are you mailing purchased lists or using lists that you built yourself through funnels?

 

[Graybeard]

Email Blacklist Check - IP Blacklist Check - See if your server is blacklisted

mxtoolbox.com

Check your IP AND the Domain that you are using First.