Comcast blocking my Comcast SMTP E-mail from home.

@Again​ Thank you.

Strangely everything is working fine today.

My email is not functioning.  And my password does not work.

@JohnnyU2​ That is what I went through too.

I had to log into the main Xfinity site using our main account (the one that processes payments).
Since the password had been changed, I was forced to use the Xfinity Two Factor Authentication mechanisms to log in.

Note this happened in spite of Two Factor Authentication!

I changed all of our Xfinity passwords. After doing that I updated any passwords on the clients (e.g. Outlook, Thunderbird).
They started working again and mail started flowing, except when connected via our home network, where outbound messages still did not work until the following day.

I don't know what happened, but just prior to this I saw successful login attempts on MANY online services accounts, including Microsoft, Apple, Ebay, etc. Those services however stopped anything further due to TFA verification requirements.

@JohnnyU2 Thank you for making us aware that your password is no longer working via Forums. Can you please elaborate on what happens when you try to log into your email? Also, are you attempting to access your email through a third party email server or directly from our website?