There is a known problem some locations (east coast Verizon for sure) with IPV6 routing. The Amazon load balancer used by the SD-JSON service supports IPV6 and most OSs and providers prefer IPV6. This is causing above error, especially with EPG123.To work around the problem, you can disable IPV6 in your network settings (who really uses it anyway??) Or upgrade EPG123 to v18.104.22.168 which uses ipv4.json.schedulesdirect.org instead of json.schedulesdirect.org
The problem is not on the Schedules Direct side, but ISP or home network routing, we've been unable to duplicate the problem.