The image you posted is not detailed enough to be sure, but it is most likely a phishing email, a scammer attempt to steal login and account information. You can check suspicious messages with Comcast's Xfinity Connect webmail: look for the XFINITY Verified Email logo next to any message that claims to be from Comcast/Xfinity (see https://www.xfinity.com/support/articles/comcast-verified-email).
Please see Comcast Email Phish or Legit? How to Tell (and rules for posting) for more information about identifying, reporting, and posting phishing emails. The article is somewhat out of date, but still useful.
Samples of recent phishing messages can be found at http://constantguard.comcast.net/help/alerts under "Top Phishing Scams".