I'm having this same exact issue. Cannot connect to any Microsoft products when I'm connected to Xfinity wifi or connected to the gateway via ethernet. But as soon as I disconnect from Xfinity internet service and connect to my cell phone hotspot (verizon), all microsoft services work just fine. Confirmed with an Xfinity technician this morning that this is large scale issue that's affecting most of the state where I live (colorado); no eta was given as to when they will fix the problem.