...Comcast. ..rolled out a new email platform in the middle of February and every since I've been having a lot of issues viewing my email from their website. I go to the Xfinity webpage and click on the email icon. That opens a new window with the email. Within 10 to 20 seconds the spinning beachball appears on both the main window and email window. ...
In addition to email, you can also watch TV from the Xfinity website. If I click on the TV icon I get the spinning beachball and a message that says to upgrade to the latest Flashplayer plugin. I have the very latest plugin and have specifically set it to use that on Xfinity in Safari preferences. ...
I have an ad blocker extension but I disabled that and still have the spinning beachball.
Comcast keeps trying to tell me there is something wrong with my equipment.
I am having NO issues with any other website except Comcast. ...
I use Comcast as my ISP, and I'm using Safari 10.1, which uses the Ghostery extension, and I do
not have Flash installed on my MBP. (Ghostery is set to block advertising, but allows analytics & beacons on Comcast web pages.) Excepting TV, which I haven't attempted to use via the web, I have no problems logging into my Comcast web mail which I gain access just as you've described. ...So, I'm not getting a spinning beachball, nor "Safari Webcontent Not Responding."
So, while I can't offer a solution, I did want to advise I'm not having a problem with Comcast's web mail. This doesn't mean to say Comcast isn't somehow causing issues for you, but seems to me if the issue was solely on Comcast's end, I would also have a problem, which I'm not.
I can only advise to keep digging into your settings, as there's something contributing to your issue.
