https://devzone.nordicsemi.com/f/nordic-q-a/127094/nrf9151-don-t-go-to-the-ntn-nb-iot-system-modeHello there, I&#39;m developing a project with NTN using a Vivo chip, a Brazil operator chip, but I&#39;m having trouble with an nRF9151 and I&#39;m trying to put it in NTN mode, but it&#39;s giving an error when trying to change its mode and I don&#39;t know what to doen-USTelligent Community 13Fri, 20 Feb 2026 13:48:14 GMThttps://devzone.nordicsemi.com/thread/561718?ContentTypeID=1Fri, 20 Feb 2026 13:48:14 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ece31d25-e820-4e47-843c-5413715d8a5aSyed Maysum Abbas Zaidi<p>Hi,</p> <p>Error 522 on&nbsp;on&nbsp;<a href="https://docs.nordicsemi.com/bundle/ref_at_commands_nrf91x1_ntn/page/REF/at_commands/mob_termination_ctrl_status/xsystemmode_set.html">%XSYSTEMMODE</a>&nbsp;means “Band configuration not valid for selected mode&quot; and it means for the current SIM/operator configuration, the modem finds no valid NTN bands (23/255/256) and therefore rejects the mode as mentioned in the documentation.</p> <p></p> <p>So your AT sequence is correct, the issue is due to operator restriction on those NTN bands.</p> <p>Best Regards,<br />Syed Maysum<br /><br /></p><div style="clear:both;"></div>