Why is my VZW GPXL1 not working with my IPTV Smarters app?

[Android Central Question]

I've been trying to connect my Xtream account to my IPTV Smarters app and it continues to tell me "network error occurred. Please check connection." I have the app installed on other devices with no problems but for some reason I can't get it to work, even on strong WiFi signal or mobile data. Any advice would be appreciated. Thanks.