https://devzone.nordicsemi.com/f/nordic-q-a/75319/ant-ble-multi-protocol-communication-problemDear friend， Based on SDK15.3, using S332 protocol stack, running on nRF52832-QFAA. Connect the device with a mobile phone via Bluetooth. The connection parameter Min connecion interval is 30ms, Max connecion interval is 60ms The number of devices sendsen-USTelligent Community 13Wed, 19 May 2021 13:04:19 GMThttps://devzone.nordicsemi.com/thread/310466?ContentTypeID=1Wed, 19 May 2021 13:04:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9463b499-bd4d-481e-abd3-67a2c51361f2Kenneth<p>Hi,</p> <p>If there is no error message from <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s132.api.v7.2.0/group___b_l_e___g_a_t_t_s___f_u_n_c_t_i_o_n_s.html?cp=4_7_3_1_2_4_2_4#ga313fe43c2e93267da668572e885945db">sd_ble_gatts_hvx()</a> then this sounds like an issue on the phone side, maybe you need to add some application handshake to not overflow the phone (e.g. every 100notifications wait for a write command from the phone before next 100notifications etc.).&nbsp;</p> <p>It would be interesting if you can make an on-air sniffer log, so we can see exactly what is happening on-air, and possible which packets are lost. Possible compare the working with the failing.</p> <p>Kenneth</p><div style="clear:both;"></div>