@User_8bs01h 

This just happened. All attempts to access my email or log in to any xfinity site using the Firefox browser (v. 147.0.3 (64-bit)) have failed. I get an "enter user name" box and then the message:

Access Denied

You don't have permission to access "http://login.xfinity.com/login" on this server.

Reference #18.87ed2117.1771191441.7c781e37

https://errors.edgesuite.net/18.87ed2117.1771191441.7c781e37

I'm using Chrome to post this (since I also couldn't log into the forums with Firefox).

I don't close Firefox when shutting down my computer for the night, and ordinarily a window with my email is available when I boot back up. Today, when I turned to that window I instead got the login box followed by the error message.

I'm unaware of any updates to Firefox that happened overnight, but when I logged into my email with Chrome, I got for the first time the message about migrating to Yahoo. That's the only change of which I am aware.

What happened?

Thank you for any explanation--especially one that provides a solution!

Have you cleared your cache and cookies?  Signed out [if applicable].  Closed your browser and started a new session?  Then try this link to get your email: https://connect.xfinity.com/appsuite  

Have you migrated to Yahoo! Mail?