[HELP] Unable to Connect to Battlenet, Twitch, Discord, Etc.

Hi all,

Just switched modems to the Arris TG1682G and 150 MB/s plan with Xfinity and am now all of sudden unable to connect to get certain applications to connect to their host services. As examples, Battle.net can't connect to blizzard, Discord can't connect and never gets past "looking for updates", Twitch desktop app DC's within seconds of startup, etc. I am hardwired into the modem from my desktop. 

I've found the following forum link: https://forums.xfinity.com/t5/Your-Home-Network/Connectivity-Issue-with-Game-Servers/m-p/2123790#M43694

which seems to address my exact issue however I'm not going to pretend that I understand how to actually implement the solution. Would appreciate any help as this is extremely frustrating...paying a ton for internet that I can't effectively use. If you understand the solution provided in the link, could you please explain it to me like I'm 5 years old...happy to provide any info required to do so. 

I've already done the following to try and troubleshoot: uninstalled Norton, temporarly disabled windows firewall, extended power cycles, flushed DNS. 

Thank you all.