My N900t on straight talk still works fine with its hotspot toggle but on my wife and daughters i317 it has stopped working they are both rooted they were upgraded to 4.3 one (my wife's) via OTA with the mk6? bootloader but my daughters I justed the older bootloarder but now they both will not hotspot natively. I had been using an app that bypassed this problem but not I get a message saying the carrier authentication has failed.
Same thing also for a little ZTE z990g phone I been playing with for my father. It is also giving similar message about authentication fail. it is rooted and has custom rom on it .
Have carriers found a way to identify wifi tethering and block/not allow it?
This has just been over past few weeks