SMTP server issues

I have been using the Comcast/Xfinity server for several years with no issues. Today I received an error from my Gmail client that my SMTP is misconfigured. I checked the settings and they are per the Xfinity support FAQ i.e.

smtp.comcast.net port 587

Secured connection using TLS

Username: my_xfinity_username

Password: my_xfinity_password

I checked both username/password was correct by logging onto Xfinity.com

Xfinity uses a single username/password for both Web and SMTP access

I pinged smtp.comcast.net and it returned:

smtp-p.gslb4.comcast.com

but I received an error that the host was uncontactable

I suspect the SMTP server is down. Or there is some username/password validation issue

What say you?