Skip to main content
user_vqzg2t
1st Topic

Visitor

 • 

3 Messages

Tuesday, July 8th, 2025

Ongoing Throttling Issue (Error RL000010) – Request for Support

Dear Xfinity Support,

We are seeing repeated throttling with the error:
451 4.2.0 Throttled - https://postmaster.comcast.net/smtp-error-codes.php#RL000010

Our emails comply with all standards (SPF, DKIM, DMARC), and we are a Validity Certification member.
Not sure why this continues—would appreciate your help in resolving the issue.

Question

 • 

Updated 

16 days ago

62

1

0

Oldest First
Selected Oldest First
XfinityBillie

Official Employee

 • 

3.5K Messages

21 days ago

 

user_vqzg2t Thank you for taking the time to reach out to us here on our Xfinity Forums! I understand that you are seeing issues with your emails being sent. Just to confirm, are these emails you are trying to send to Comcast.net emails that are not going through? For concerns such as these you would want to open a ticket for our Customer Security Assurance team by visiting this site: https://spa.xfinity.com/report. THeir team would have access to the correct tools to help you with resolving your concern. 

 

5

0

user_vqzg2t

Visitor

 • 

3 Messages

Hello @XfinityBillie​ , we’re getting a lot of 451 4.2.0 Throttled (RL000010) errors when sending to @comcast.net addresses.

Our domain has valid SPF, DKIM, and DMARC, and we're a Validity certified sender. Mail is fully compliant, but throttling still continues.

I have tried to submit a ticket under the site you gave a while back. They replied me that the IPs we were using were not blocked and they cannot help us.

Could you please help review or reset the reputation for our domain/IP?

Happy to provide more info if needed.

Like

Reply

20 days ago

0

XfinityChelseaB

Official Employee

 • 

1.9K Messages

@user_vqzg2t, Are you a Comcast Business Customer?

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

Like

Reply

20 days ago

0

user_vqzg2t

Visitor

 • 

3 Messages

@XfinityChelseaB​, No, we're not a Comcast Business customer. We're sending from a third-party email platform to @comcast.net recipients, and are experiencing persistent throttling issues (RL000010) despite full compliance. This is impacting our ability to reach customers who use Comcast email and hurts time-sensitive transactional emails.
Happy to provide domain/IP via DM if needed.

(edited)

Like

Reply

17 days ago

0

XfinityAlyssaA

Official Employee

 • 

2.1K Messages

Thank you for confirming you are not a business customer @user_vqzg2t, we appreciate it. Unfortunately, this is outside our scope here on this platform. I would recommend trying to reach back out to our dedicated Customer Security Assurance (CSA) Team. They can be contacted directly at 1-888-565-4329 and their hours of operation are 8:00am - 12:00am EST, 7 days a week.

 

 

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

Like

Reply

17 days ago

0

XfinityAlex

Official Employee

 • 

930 Messages

@user_vqzg2t​ Please send me a DM with the details.  I can likely help you properly.

Like

Reply

16 days ago

0

forum icon

New to the Community?

Start Here