For the past few days, I have been having connection issues on specific games on both my PC and PS4. I know it is ISP related as my friend who lives next to me is not experiencing these problems, on a different provider, and Ubisoft made a post on their forums stating that there were problems with users on Comcast on their servers. The games being affected are Tom Clancy's Rainbow Six Siege and NBA 2K20, as I cannot connect to the servers on both my PC and PS4. Is there any fix to this? I have restarted my gateway multiple times and done what the Xfinity Assistant has told me to do. I am also not getting advertised speeds, I am paying for Gigabit, but only getting 175-200mbps download, but I don't really care about that. Also, both devices are port forwarded.
I forgot to add that this has also been confirmed through use of a VPN, where the games worked completely fine, but with a very high ping.
Try disabling the Xfi Advanced Security feature as a work-around for now and see. It's buggy ! And there is currently no way for an end-user to be able to whitelist anything;