Visitor

 • 

3 Messages

09/24/2026 9:28 PM

outgoing smtp server encryption error

I am getting this message when trying to use Xfinity to send mail from Outlook. "Your server does not support the connection encryption type you have specified. Try changing the encryption method. Contact your mail server administrator or Internet service provider (ISP) for additional assistance."

I am using the exact information from Set up your Xfinity Email address with an email program

Outgoing Mail Server Name: smtp.comcast.net
Outgoing Mail Server Port Number: 587 (SMTP)
Encryption: TLS/SSL 

Oldest First
Selected Oldest First

Expert

 • 

35K Messages

16 hours ago

@user_rt2c9z 

You don't say what device you're using.  Are you Apple/Mac? or PC?

If PC try these settings:

Outgoing Mail Server Name: smtp.comcast.net
Outgoing Mail Server Port Number: 465 (SMTP)
Encryption: TLS/SSL 

Authentication Method: OAuth2

Visitor

 • 

3 Messages

I'm using Outlook (Classic) in Windows 11. I am not familiar with OAuth2 as an authentication method so I need to do some research. It appears that this is not something set in Outlook. 

(edited)

Visitor

 • 

3 Messages

I fixed it. Comcast now requires you to explicitly authorize 3rd party access. It took a while, but I found the checkbox to allow this.

forum icon

New to the Community?

Start Here