You’re not alone…
Users all over the country are finding out daily that suddenly, for no apparent reason at all, they are unable to send mail if they want people to reply to their business or personal e-mail addressed other than one that is @comcast.net. This is because Comcast is blocking port 25 , which is your default port for sending email through your mail software.
The error message says (fill in your own X):
The connection to the server has failed. Account: ‘XXXX’, Server: ‘xxx.xxx.xxx.xx’, Protocol: SMTP, Port: 25, Secure(SSL): No, Socket Error: 10060, Error Number: 0x800CCC0E
Gee that’s helpful, isn’t it?
If you are using mail.yourdomain.com for your SMTP outgoing mail server, then you get an error saying “unable to connect to the mail server” even though it just successfully connected to the mail server to retrieve your incoming mail. After wasting time calling your web host, and going through various troubleshooting techniques, they tell you to call Comcast.
To make matters worse, users are finding out one at a time, because Comcast is slowly rolling out these changes user by user in individual markets around the country. This month, it’s apparently Portland Oregon’s turn, where I live.
To cut to the chase, here’s the solution:
Change the port your computer is using for SMTP outgoing mail, from Port 25 to one that your hosting provider will allow. In most cases, this seems to be port 587 for Portland providers.

To do this in Outlook -
- Go to tools – e-mail accounts – view or change existing account
- Sselect the appropriate mail account and hit the change button
- Go to the more settings button, and into the Advanced tab
- Change your default port 25, to port 587, and you should be back in business in most cases.
Still broken?
- Added note from comments below – Some people in the midwest for whom 487 didn’t work succesfully chaged to 465 and picked SSL under the “use the following type of encrypted connection” drop down. They did not check the “this server requires an encrypted connection” box.
In Outlook express -
- Go to tools – accounts – Mail tab
- Choose Properties box – Advanced Tab – and from there you can do the same
The reason Comcast claims to be doing this is in an effort to prevent spam being sent by zombie/spyware/virus laden computers using their bandwidth and their Internet connection.
I suspect they are really doing it to limit liability for any future potential lawsuits, and not really to save bandwidth, but I have no problem with that.
The problem with Comcast doing this is that they do not seem to be telling all of their support people, and do not be notifying their customers. This has been going on around the country for MONTHS.
Instead, it takes the end user hours of frustrating time on the phone spent with lower-level tech-support who have no idea that this change has even taken place.
One can only guess how many individual users are still frustrated at this very moment because they are being forced to do their business e-mail from home using their @comcast.net accounts, after uninformed Comcast agents are able to help them?
As a web host, we were forced to spend hours dealing with Comcast before we got an actual answer, and we still lost a couple of hosting customers over it, who were convinced that it must be our fault, since Comcast told them it was.
Great customer service. If there was any competing product in my market I would switch in a heartbeat. I tried once before in 2005 after nearly an entire summer of poor Comcast connectivity.
Thanks Comcast, for valuing our time so very little, in your quest to make mega millions.
























Scott,
Thank you so much! I am also in PDX and started experiencing this problem with Comcast yesterday.
I used 465 and picked SSLI and that fixed it!
I can’t believe I found this! I’m in Portland, OR, and it worked just as stated above. Thank you for the information and for shareing.
I live in Houston, Texas, and changing the outgoing server to “587″ worked for me too. Thanks!!
Thanks VERY much! I started experiencing this problem in Tucson today – and changed my port to 587 and this fixed the outgoing mail problem!
We have a lot of residential Comcast customers that have just started reporting connection issues due to Comcast restricting both inbound and outbound communications over the standard SMTP port 25. We offer a SMTP Relay service for individuals that allows you to send mail over alternate ports which are not blocked by Comcast. If you are running an on-premise mail server and can’t receive eMail any longer, we also have a Store and Forward service that will redirect your mail to a different TCP port.
For more information:
http://www.unifiedemail.net/Service/Default.aspx
That’s not quite the end of the story.
In addition, it’s important to point out that you MUST use Comcast’s domain to send mail now. (Previously you could send using your own e-mail server as the SMTP server.
You MUST have a Comcast e-mail account (you got one when you signed up…and if you forgot your password because you never use it, you may need to get a reset.
SENDING MAIL:
SMTP Server: smtp.comcast.net
Advanced Sending Options:
x SMTP Service requires secure connection (SSL)
x Ovderride default SMTP port: 465
x SMTP server requires authentication
x Log on using
Account ID: yourid@comcast.net
Password: your-comcast-password
x Save password in my Mac OS keychain
Also, you must ensure that your e-mail hosting service supports the ports that Comcast provides.
Mine did NOT support 587. However they DID support 465 using SSL.
Check with your own hosting company.
I made 15 calls to Comcast before I could find a competent customer service rep who could help me. Even then she didn’t have all the answers, but she spent over an hour with me until we DID get the answer.
They really want to sell you Xfinity Signature Services to fix your problem. Create the problem, then sell the solution…. great business plan, right?
Don’t let them get away with it!
587 worked like a charm. THANKS!