Help & troubleshooting for network issues, including connecting your device to your home Wi-Fi network, connecting to public networks, troubleshooting wireless issues & ethernet connections, and optimizing streaming performance.
When Time Zone is set to Auto, it determines where you are by your public IP address. AT&T is obviously using an Internet access point located in the Dallas area. I get the same thing with my work computer when connected to the FAA network. Our Internet access point is Oklahoma City, so I get all sorts of web page ads for stores and services in the OKC area, and I'm in Seattle.
Your only solution is to set the Time Zone manually in the Settings/System/Time menu. Change "Set automatically" to "Set manually" and set it to Mountain Time, assuming you want the Denver TZ.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.