Net Down

On Monday 22 my netbuddy/ATT internet went down. On the nighthawk is show mobile broadband disconnected. Signal is 3 bars but has H where the LTE was. I log into Netgear app and it says unable to connect to the network. Check your APN settings and try again. Monday I perform factory reset but still coming up with the same issue. I tried some old APN setting found on Netgear community but still no luck.