[Solved] Collaborate no working on Xfinity ISP

All of the sudden collaborate has stopped working when I am working at home on Xfinity Gigabit internet. It works fine if I connect to another network. I don't believe its a DNS issue because i am set to use google's DNS. Any idea what might be getting blocked causing this. I typically get a "no internet connection" error message trying to sync. But if I switch to another wifi (tether to LTE) I am instantly fine.

 

Problem resolved. You can thank Xfinity's auto threat detection for blocking the connection.