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user_4mwirz
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Monday, March 17th, 2025 9:42 AM

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

Hello,

We are currently encountering issues when sending emails to Comcast.net recipients, receiving the following error message:

"530 5.1.0 Sender Rejected"

This issue began at the start of this month, and prior to that, we had no issues sending emails to Comcast.net addresses. After reviewing our configurations, we can confirm that our IP addresses are not listed on the Spamhaus database or any other RPBLs, and our email server is properly configured. Since our IP addresses are clean and not blocked, we would like to clarify that none of our IPs appear on any blacklist. I initially contacted the Comcast Postmaster removal service, which asked for blocked IPs; however, my IPs are not blocked. Upon further testing directly from my mail server, it became clear that the issue lies with my domain being blocked. When sending emails from another domain  the emails are successfully delivered from the same mail server. We believe that our domain, "exactverify.net," has been mistakenly flagged or blocked by your email filtering system. 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.

Question

 • 

Updated 

12 days ago

91

2

0

XfinityPeterH

Official Employee

 • 

1.8K Messages

24 days ago

@user_4mwirz 

Thank you for reaching out and providing detailed information about the issue you're encountering. I understand how frustrating it must be to have your emails to Comcast.net recipients rejected, especially when your IP addresses are clean and properly configured.

I appreciate your patience and the steps you've already taken to troubleshoot this issue. Based on your description, it seems that your domain "exactverify.net" may have been mistakenly flagged by our email filtering system.

To resolve this, please contact our Customer Security Assurance (CSA) team at 1-888-565-4329. Their hours of operation are Monday to Friday, 6 a.m. to 2 p.m. PST We are committed to ensuring your issue is resolved promptly and appreciate your cooperation.

5

0

user_4mwirz

5 Messages

@XfinityPeterH​  Thank you for your your help in directing me to the right point of contact for further assistance. Could you please provide me with the email address to contact the Customer Security Assurance (CSA) team? 

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23 days ago

0

XfinityRoberto

Official Employee

 • 

1.7K Messages

Hi there @user_4mwirz. Now we do not have a direct email for them. You can actually go to https://spa.xfinity.com/help/postmaster?faq=avoid-blocks-ipv4 and scroll down to where it says Postmaster. Click on Postmaster and scroll down to where it says Report an issue. Click on Report an issue and it will take you to our page were you can report the issue you are having. 

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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23 days ago

0

user_4mwirz

5 Messages

@XfinityRoberto 

Hello,

We reached out via the postmaster, but it seems there was a misunderstanding, and they mistakenly thought the IP was blocked. Unfortunately, due to the no-reply email, we couldn’t clarify the situation. It appears that our domain, "exactverify.net," has been flagged by your email filtering system. Could you kindly unblock the domain? Alternatively, if necessary, we can DM the appropriate person to resolve this issue. We would greatly appreciate your assistance in addressing this matter.

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22 days ago

0

XfinityRoberto

Official Employee

 • 

1.7K Messages

If we could unlock the domain, we would be happy to do so. I would recommend opening another ticket bia the postmaster process and explainin that the IP is not blocked. 

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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22 days ago

0

user_4mwirz

5 Messages

Hello,

@XfinityRoberto @XfinityPeterH​

Thank you for your previous responses. However, we have again submitted a request through the postmaster process and clearly explained that our IP is not blocked. Despite this, we have received the same response for the last two times we have applied. Below, I’ve included the responses I’ve received for your reference.

Could you kindly assist us in removing the block on our domain? Else we would appreciate your help in explaining the situation to the postmaster team, in behalf of us. This issue has been ongoing for a long time and is significantly affecting our email deliverability. We would greatly appreciate any support to resolve this and remove the block.

Here are the responses I received from the postmaster:


Your Comcast Blocklist Removal Request
Thank you for contacting Comcast Service Policy Assurance. We've received your request to remove your IP(s) from our blocklist. Of the one IP(s) you submitted, none were on our blocklist..
If you've received error code BL000000 previously, it may mean this IP was temporarily blocked, or that someone else requested we remove it from our Blocklist. Please note: if this IP exhibits malicious activity in the future, it may be blocked.
If you received an error code other than BL000000, please follow the link contained within the error for more information and troubleshooting. Alternatively, you can review the error code information in our Frequently Asked Questions here.

(edited)

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22 days ago

0

user_4mwirz

5 Messages

12 days ago

@Xfinity Support could you please assist us by providing a solution?

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