Unable to send out emails.

Hello Scott, can you please copy the content of the log rather than including a screenshot in your next reply as it is not possible to read the whole error message from the screenshot?

Based on the partial error, I believe you might be using a firewall or your account may be setup incorrectly. Try to temporarily disable any security software on your computer and check if the issue persists.
If it does, please submit the whole content of the log here on the forum and make a screenshot of your SMTP settings in Tools > Accounts > Your comcast account.

Thank you.

Hello Scott, as I’ve mentioned in my previous comment, seems like the connection is being blocked, either by a security network element or software on your computer - such as firewall, proxy or antivirus software with email protection. Or the connection might be blocked by the server, but in most cases this error occurs when local firewall or proxy is blocking the connection.

Please try to temporarily disable such security elements on your computer or in your network or setup an exception for eM Client and check if the issue persists.