xfinity is blocking access to websites

Is there a way to request a review when you find that xfinity is blocking access to a website, possibly for security reasons, but where the website is valid? There is a website that I am presently unable to access through xfinity Internet, even though it loads through other services, and I would like to be able to browse to that site.

Related thread,

xFi Advanced Security is blocking my company's website

https://forums.xfinity.com/t5/Xfinity-App/xFi-Advanced-Security-is-blocking-my-company-s-website/td-p/3305727

(In that thread, @ComcastJosh was offering to help users with this type of problem. I don't want to randomly contact him.)