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Monday, April 14th, 2025 11:02 AM

530 5.1.0 Sender Rejected for all emails sent to Comcast.net customers

Hello,
We are currently experiencing issues when attempting to send emails to comcast.net recipients. Specifically, we are receiving the following error message:

The response from the remote server was: 530 5.1.0 sender rejected

This problem began earlier this month. Prior to this, we had no issues in sending emails to comcast.net email addresses. After thoroughly reviewing our email configurations, we can confirm that our IP addresses are not listed on the Spamhaus database , RPBLs or any other real-time blocklists, and our email server is properly configured. To clarify, we are not having the BL000000 block, our IP addresses are not blocked, but rather, our domain has been blocked. I initially reached out to the Comcast Postmaster removal service, which asked for the blocked IPs; however, as mentioned, our IPs are not blocked. Upon further testing directly from our mail server, we discovered that the issues are from our domain being blocked, not our IP addresses.

When sending emails from another domain using the same mail server, the emails are successfully delivered, confirming that the issue is isolated to our domain, "exactverify.net." We believe that our domain has been mistakenly flagged or blocked by your email filtering system. This issue is significantly impacting our ability to communicate with comcast.net users. Therefore, This issue is affecting our ability to communicate with Comcast.net users. We kindly request that you review the status of our domain and remove the block as soon as possible. We have also reviewed similar cases within Xfinity, where users have sought a resolution by having the domain block removed. We are requesting the same resolution. For your reference, we have attached links to these cases below:

[https://www.reddit.com/r/Comcast_Xfinity/comments/1hqnioh/delivery_status_notification_failure_when_sending/]

We appreciate your prompt attention to this matter and look forward to your assistance in restoring our email deliverability.

Thank you.

Expert

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109.8K Messages

5 days ago

The concern is not "Community Center / Guidelines" related............ Topic moved here to the proper help section, and for greater exposure to Comcast corporate employees (The Digital Care Team) for assistance. 

Official Employee

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1.2K Messages

5 days ago

 

user_4mwirz

Thank you for reaching out regarding the issues you're experiencing when sending emails to Comcast.net recipients. I understand how frustrating this can be, and I'm here to help you resolve it.

Based on the error message you provided, it appears that your domain "exactverify.net" has been blocked by Comcast's email filtering system. Here are the steps you can take to address this issue: 

  1. Review Similar Cases: There have been similar cases reported in the Xfinity Community Forum where users experienced domain blocks. You can refer to these cases for additional insights and solutions.

  2. Contact Customer Security Assurance: If the block persists, you may need to contact Comcast's Customer Security Assurance at 888-565-4329. They can provide further assistance and potentially expedite the removal of the block.

  3. Ensure Compliance: Double-check that your email server complies with all necessary standards, such as proper rDNS records and adherence to sending limits. This can help prevent future blocks.

I hope this helps! If you need further assistance, feel free to ask.

 

8 Messages

@XfinityWilliam​ 

Could you please provide an email address for the CSA Team so we can send a detailed explanation to help them better understand the situation? Alternatively, if possible, we would appreciate your assistance in connecting us with the appropriate CSA team or notifying them about this issue on our behalf.

We’ve thoroughly verified everything on our end and found all configurations to be in proper order. Based on our assessment, it appears that our domain has been blocked. We’ve attempted to contact Xfinity support, but they were unable to recognize or understand the nature of the issue. This is why we are seeking a more direct way to communicate and clarify the situation with the CSA Team.


Official Employee

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2.7K Messages

Thank you for all the steps you have taken to get to the root cause of this, user_4mwirz. The CSA team can be reached by calling 1-800-XFINITY and requesting that team or by trying the number listed above. There are some email address for that team to report Spam or things of that nature but nothing to address this particular concern through email. We recommend giving them a call. 

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8 Messages

Hello,

@XfinityRay
Thank you for your response. We understand that calling may be the most effective option, and we will proceed with that as well. In the meantime, could you please share any relevant email addresses where we can report the issue to the team.

Official Employee

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1.7K Messages

 

user_4mwirz You are most welcome, we are happy to help in any way we can! To be honest, we don't have a specific email address, but you can submit your concerns electronically if that's easier. Please feel free to let us know if there are any other concerns we can assist you with. 
 
https://spa.xfinity.com/report 

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
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