The blocking site may have read safebrowse.io. The "proceed anyway" link just reloads the site...which just get blocked again!
Using the Xfinity website (there is alternatly the Xfinity xFi phone app)
1: Login to xfinity account.
2: Click the wifi icon on the tool bar. If you hold the mouse over it the tool tip will show Xfinity xFi.
(wifi icon is to the left of the phone icon)
3: You should now be at
https://internet.xfinity.com/
4: Click on More...you will land here
https://internet.xfinity.com/more
5: Click on My Services.
6: You will be at xFi Advanced Security...click Disable (or Enable).
7: You will be presented with a toggle button to select enable or disable.
It says to wait about 10 minutes for change to take effect