https://devzone.nordicsemi.com/f/nordic-q-a/40026/how-to-solve-the-stop-scanning-due-to-unknown-reasonHi, everyone, We are developing BLE project on nRF52832 chip by using SDK14.0 software. The project is build from one master-device and many slave- devices. The master device must establish connection to one of the slave-devices from time to timeen-USTelligent Community 13Thu, 01 Nov 2018 14:55:33 GMThttps://devzone.nordicsemi.com/thread/155600?ContentTypeID=1Thu, 01 Nov 2018 14:55:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1227dfbb-f88b-4bf6-abeb-37383920b1ebbjorn-spockeli<p>Hi Boris,&nbsp;<br />after calling&nbsp;<span>sd_ble_gap_connect() you should get the BLE_GAP_EVT_CONNECTED if you successfully connected or the BLE_GAP_EVT_TIMEOUT if the connection establishment timesout. If you call sd_ble_gap_connect_cancel it will return NRF_SUCCESS if the connection establishment is cancelled,&nbsp;</span><span>see&nbsp;<a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v5.0.0/group___b_l_e___g_a_p___c_e_n_t_r_a_l___c_o_n_n___m_s_c.html">Central Connection Establishment and Termination</a>.</span></p> <p><span>So you should be able to restart scanning by calling sd_ble_gap_scan_start when you get&nbsp;BLE_GAP_EVT_CONNECTED&nbsp;or&nbsp;BLE_GAP_EVT_TIMEOUT or after you call&nbsp;sd_ble_gap_connect_cancel(). You state that this does not work, do you get any error code from <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v5.0.0/group___b_l_e___g_a_p___f_u_n_c_t_i_o_n_s.html#ga3db84fa4870b155489187103906cf318">sd_ble_gap_scan_start</a>&nbsp;&nbsp;indicating that scanning is not started?</span></p> <p><span>Best regards</span></p> <p><span>Bjørn&nbsp;</span></p><div style="clear:both;"></div>