https://devzone.nordicsemi.com/f/nordic-q-a/73276/cannot-reconnect-device-using-nrf52811-after-unpair-on-ios-and-android-phoneDear Nordic support team. Our product nearly complete Rnd stage. We face only one thing relate to &quot;Cannot reconnect after unpair device with smart phone&quot;. debug wit RTT Viewer: &quot;Connection security failed: role: Peripheral, conn_handle: 0x0, procedureen-USTelligent Community 13Mon, 19 Apr 2021 08:03:18 GMThttps://devzone.nordicsemi.com/thread/305428?ContentTypeID=1Mon, 19 Apr 2021 08:03:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1c287f0d-6d4b-43f2-93a4-e83a4a25123bJoakim Jakobsen<p>Hi.</p> <p>When you &quot;unpair&quot; the device from the smartphone. Have you made sure that the bonding information is erased from both the phone and the nRF?</p> <p>If only one of the devices erases the information you will have trouble reconnecting or re-pairing.</p> <p>Br, <br />Joakim</p><div style="clear:both;"></div>