Comcast Email Not Sending – Fix Yourself

Comcast not sending email causes inconvenience to its users.

Sending and receiving emails has become an integral part of this digital age. However, every technology sometimes and somehow catches some problem. If your Comcast email won’t load or causes problems sending an email, keep reading this article in order to fix the issue.

Why is my Comcast email not sending?

If your Comcast won’t send emails, there can be one of the several reasons behind it. Comcast not sending emails can be because of poor internet connection, attachment issues, syncing error, SMTP settings error, etc. In the further article, we will fix your problem by first understanding the exact problem.

Before proceeding, we would suggest you to try sending emails to multiple users and that too without any attachment.

We recommend reading this article holistically because there might be more than one reason for your Xfinity email not sending.

Is Comcast receiving emails but not sending?

Comcast Emails Not Sending

The reason behind Comcast receiving but not sending email is improper settings. As most (if not all) of us know, SMTP (Simple Mail Transfer Protocol) is responsible for sending emails from the user to the server. If there is some mistake in entering SMTP server and port, the email won’t send.

Fix SMTP Settings

You can change the SMTP settings on Outlook or Mac Mail from the account settings.

The correct SMTP settings for Comcast are as follows:

Port: 465 or 587
Security/ Encryption: TLS (preferred), SSL/TLS, or SSL

To fix Comcast not sending email from Outlook or Outlook express, Go to File tab > Account settings, select email address and click change. Then go to More settings (lower right) > Advanced, and enter the correct settings.

To fix Comcast email not sending on Mac Mail: Go to Mail > Preferences > Accounts. Select the Xfinity / Comcast email address, click server settings, and enter above mentioned settings.

Are Comcast emails not sending only to a particular account?

Since you are not able to send or receive emails from particular account(s), this might be because either you or the designated receiver has blocked the other. If that is not the case, the receiver is not able to receive an email due to certain settings or any other reason.

Unblock the account or get yours unblocked

If you had blocked someone inadvertently or for a reason, you won’t be able to send and receive emails from them until unblocked. Same is also true for the opposite user. Go to email settings to check the block list and unblock the user. Conversely, ask the designated receiver to do the same.

Check the email address

Cross check the email address you are entering in the receiver’s ID box. Spelling mistakes and typos in the email address would render the email undelivered and you will receive an email confirming the same within some time.

Ask the receiver to check his/ her settings

Other reason for receiver not receiving your emails are the recipient mail box settings. Ask him to check and enter the correct IMAP or POP (POP3) settings in the account settings.

Is Comcast not sending emails with attachment?

Comcast Email Not Sending

Have you tried sending emails without attachments? If there is no problem in sending emails without attachment, then the problem is either with the attachments’ size, internet connection, or both.

Attachment size is big

Big size attachments take longer time to send. Try compressing the attached files into smaller size. If compressing is not a feasible option for you, try dividing the attachments into multiple emails. This way, you can track which attachments are sent, and individual mails get sent in lesser time.

Internet is slow

When you are sending attachments without good internet connection, it would keep showing either queued or sending for a long time. Try running an online speed test to check the connection speed.

Is your Comcast email not syncing with the server?

Comcast Email Not Sending

Comcast had added a new security feature in Xfinity Connect email. From Septemper 16, 2020, users get a new security checkbox that allows them to enable and disable access to third party email clients.

If you enable third party access, your data might be at risk of breach by third party email clients such as Outlook, Mac Mail, Thunderbird, etc.

However, disabling third party access would take over your privilege to use Comcast email on other email clients.

When you disable third party access, the email will stop syncing with the cloud and won’t send/ receive any email or would show a generic error.

Change third party usage settings

To continue using Comcast on third party email clients such as Outlook, Outlook Express, Mac Mail, etc. turn on third party usage from the Comcast settings.

Follow these steps to send and receive emails on third party apps by turning on Comcast third party usage.

  1. Firstly open Mailbox, click Gear icon, and select Settings.
  2. Click on Security.
  3. Uncheck the box against Third Party Access Security.
  4. Now you can use Comcast or Xfinity connect email on third party email clients.


This article helps you with not being able to send emails on Comcast. After holistic reading of this article, you can fix the problem yourself.

We would recommend you to follow Comcast Support page where you can troubleshoot all problems related to Comcast.


Why is Outlook express not sending email via Comcast?
Outlook express not sending Comcast email because of Third party Access settings. Change third party access settings from Comcast Mail Box > Settings > Security > Third Party Access Security.

What is the outgoing mail server for Comcast?
The Outgoing mail server for Comcast is

How do I fix an SMTP error?
You can fix SMTP error by re-adding the email account into the email client with right SMTP settings.

Is Comcast email POP or IMAP?
You can use both POP3 and IMAP on Comcast email. However, the company recommends using IMAP so that you can easily read emails on multiple devices.

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