I've had this Error for a month now (Please clear your browser's cache). No resolution. Mac OS. Chrome Browser. Cleared browser cache, cookies, etc several times and no resolution (as you've seen on this community forum since 2018). Replaced new modem/router (per Xfinity tech on chat) after restarting dozens of times . Still not working.
Tech came to the house to check lines as after my 4th call. (Xfinity rep on a phone call said I was losing packets, thus sent a tech). This tech fixed some line loss inside and outside the house. He also suggested to FLUSH and RESET ALL DNS Cache. I thought this would work... but it didn't.