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

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internet interference, a security setting (like a firewall or antivirus program blocking the send request), or even outdated server settings if they changed recently.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.