Comcast Email Permanent Error Message – Permanent error sending to specific email address

by admin | Posted on Tuesday, October 12th, 2021

Xfinity Comcast is primarily known for its high-speed internet. If you are a subscriber then you might know that it also offers a fairly capable email service as well. Without a doubt, Comcast email is a feature-rich service that works smoothly most of the time. However, there are some technical errors present in this email service that can literally ruin the overall experience. 

Some of the technical errors are temporary while others are permanent. In today’s post, we will talk about Comcast Email Permanent Error. These errors generally appear when you try to send emails through your Comcast email account. Go through this post to know more about Comcast Email Permanent Errors along with their easy solutions.  

What are Permanent Email Errors?

Permanent errors appear on your screen when your recipient’s server returns the email to the server from which you are sending it. Generally, this applies when the email address of one or more recipients is not correct or is no longer active. So, they can’t receive emails anymore. Receiving a permanent error while sending an email is very common.

 For example, when you use your company’s or business email as a contact and later stops working for the company then that email address gets terminated. So, when another person tries to send an email to that email address will have to face a permanent email error. Some other reasons for these errors may include the following:

  • Invalid email: The errors message indicates that  the email address of one or more recipients is missing or incorrect. 
  • Inbox: You will face this error when the server doesn’t find the recipient’s inbox. The inbox no longer exists or moved to another location. 
  • Syntax error: This one is the most common type of Permanent Error Message. It appears when the email domain provider finds characters that are not allowed. For example – you can’t have a space in any email address. 
  • Returned: This kind of permanent error occurs when the server receives the email, recorded as delivered. However, during the later submission, sever can’t find the mailbox and then returns the email.

This Returned type of permanent error requires a lot more attention as well as care. The permanent errors are very harmful to your deliverability rate. It is so because these errors have an immediate rejection of the provider. The same is considered inactive after the first attempt. The instant and most simple solution is to remove it. It is so because if it stays on your list, all other contacts, including those contact to which you have constant interaction will have their deliveries affected. 

Solutions to general Comcast Permanent Error Codes Message

Now, let’s discuss the specific Permanent error codes that are often faced by Comcast email users.


  • Reason behind the error – You may face this error while sending an email from a dynamic/residential IP address within the Comcast domain.
  • Solution to fix it – Check and ensure that you are using the correct SMTP settings of Comcast. 


  • Reason behind the error – The error occurs when a user tries to send an email from a dynamic/residential IP space.
  • Solution to fix it – Check and confirm that you are using the correct POP/ SMTP settings. 


  • Reason behind the error – The reason behind such a problem is that Comcast filters have determined that email from your email server has been sent in patterns that are characteristic of spam.
  • Solution to fix it – Ensure that the email you are trying to send doesn’t look like spam. Don’t use phrases that make your email look spam. 


  • Reason behind the error – You have to face this issue when the IP address you are using to send a Comcast email is listed on the Spamhaus zen. Spamhaus Zen is the list of IP addresses that are flagged for sending spams. 
  • Solution to fix it – You may consider changing your IP address or visit Spamhaus Zen to ask them to unlist your IP address.   


  • Reason behind the error – This error indicates that your IP address is listed to the Return Path Reputation Network Blocklist 
  • Solution to fix it – You should contact Return Path Reputation Network Blocklist and request them to remove your IP address from their list. Your email service provider can also request the same on your behalf. 

Other Non-Specific Comcast Permanent Email Sending Error Codes

Apart from the specific error codes, you might have to face some non-specific Comcast permanent Email sending error codes. Some of these are explained below. 

421 – [Try again later] – It is a temporary error good. You don’t have to do anything in order to fix it. This error gets resolved itself after a few hours. 

452 – [Too many emails sent on this session] – Comcast doesn’t allow a user to send more than 1000 emails per session. When you try to send more emails than Error 452 appears. 

421 – [Too many sessions opened] – You can open more than 25 sessions of Comcast email using the same IP address. To fix this problem, you may close some of the currently active sessions. 

550 – [Your message could not be delivered due to too many invalid recipients] – When you try to send a Comcast email message to many users and the email addresses of some of the users are not valid then this error appears. Check the email address of the recipient to fix this problem.  

552 – [Message size exceed]  – You can’t send an email larger than 15 MB in size through Comcast. This error will occur if you exceed this limit. 

We hope that this article helped you get rid of Comcast Email Permanent Error that you are facing. However, if the problem persists, you can contact Comcast Email customer service and look for more advanced solutions. 


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