henrycfa's profile

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1 Message

Thursday, April 24th, 2025

The attempt to send data to the server "smtp.comcast.net" failed

Why does comcast fail to send email? The attempt to send data to the server "smtp.comcast.net" failed

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Official Employee

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2.9K Messages

6 months ago

 

henrycfa

Hey there — thanks so much for reaching out. I totally get how frustrating it is when your email suddenly won’t send — I've definitely been there myself, and it can feel like it happens out of nowhere.

 

When you see an error like "The attempt to send data to the server 'smtp.comcast.net' failed," it usually points to a few possible things:

 

One common cause is a connection issue between your device and the Comcast SMTP server — it could be temporary internet interference, a security setting (like a firewall or antivirus program blocking the send request), or even outdated server settings if they changed recently.

 

Here’s a quick checklist you can try to get things working again:

  • Double-check your outgoing mail settings:

    • SMTP Server: smtp.comcast.net

    • Port: 587

    • Encryption: STARTTLS (or TLS if that's the option available)

  • Make sure your username and password are up-to-date — it should be your full Comcast email address and the correct password.

  • Restart your modem/router and device — sometimes a simple refresh clears up the connection glitch.

  • Temporarily disable your antivirus or firewall (if you’re comfortable) just to see if it’s interfering with email traffic. If it is, you might need to adjust the settings.

  • If you're using a third-party email app (like Outlook, Thunderbird, Apple Mail, etc.), make sure it’s updated to the latest version. Some older apps don't support modern security standards anymore.

If you try all this and it’s still giving you trouble, let us know. We will be happy to assist you further. 

 

Visitor

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2 Messages

@XfinityAirelle​ - interested to know what the next steps would be.  I havent heard the same issue;  I can not sent email when I am connected to the Spectrum network in Montana (Comcast isn’t available here).  When I turn WiFi off and use my verizon connection on either my iPhone or iPad it works and sends fine.  To make things more complicated; the issue is random.  Occasionally ther mail sends just fine, however, ther majority of send attempt mail. 

Official Employee

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1.9K Messages

 

ms60 Just to clarify, your email works fine on other networks, and not Spectrum correct? Are you a current customer with Xfinity?

 

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

Visitor

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2 Messages

@XfinityShawn​ sorry never saw this.   I

am no longer a xfinity customer at the

moment as I moved to an area not

serviced by them.  I was told I could

keep my email as long as I actively used it.

Official Employee

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2K Messages

ms60 if the email address is working other than when you're on the Spectrum network, it may be best to start by contacting them. 

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

Visitor

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1 Message

7 days ago

where do I find where to check user name and password?

thanks.

Official Employee

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2.9K Messages

Hello, @user_mb6e7u you can use this link to locate your username. You can follow the same link to reset your password. 

 

Your Xfinity username is your Xfinity ID, which can be your email address, mobile number, or a username you set up previously. This Xfinity ID and password are the same credentials used for all Xfinity services, including Xfinity Mobile. To find your Xfinity ID, you can use the online lookup tool or check under the "Personal Information" section in your account settings or on your X1 TV box using the Xfinity Voice Remote. If you forget your password, you can reset it by following the step-by-step instructions provided on the Xfinity password reset page.

 

For more details see:

 

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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