cannot pay bill, log in, click pay button and redirects to this

cannot pay bill, log in, click pay button and redirects to this:

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

Reference #[Edited: "Personal Information"]

I'm using chrome on windows. I haven't changed anything. Paid last month just fine, paid all the other bills just fine. Re-tried a few times by just paying bill without logging in, etc.