Xfinity internet blocking Spotify

Xfinity internet is blocking access to Spotify.com and the Spotify App on my smart TV. 

I've tried all the normal stuff (resetting modem/router, plugging the devices directly into the modem bypassing the router) I've uninstalled the app on my TV, nothing works. If I open Spotify.com on my phone connected only to LTE it works, or if I hotspot the TV to my LTE phone it will work. 

Why is Xfinity blocking this specific App/site? How can I stop this from happening?

update 12/22: It seems to be working again with no action needed on my end. Apparently something Xfinity did both caused and fixed the problem.