https://devzone.nordicsemi.com/f/nordic-q-a/102424/nrf_error_invalid_length-on-ble-advertising-startupI am getting the following error periodically whenever I start my BLE application. I would say this happens 1 time out of every 10. &lt;error&gt; app: ERROR 9 [NRF_ERROR_INVALID_LENGTH] at C:\SVNRepo\ISSPRO 6279\EV3 SpeedoTach nRF52 Executable\Nordic_SDK_17en-USTelligent Community 13Tue, 01 Aug 2023 11:36:50 GMThttps://devzone.nordicsemi.com/thread/439238?ContentTypeID=1Tue, 01 Aug 2023 11:36:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2725954f-084e-4d34-b48b-07bd1f3af66chaakonsh<p>I looks like you need to increase the app scheduler&#39;s element size and/or amount. See&nbsp;<a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/group__app__timer__config.html#ga3cae0236c8e963755ec625e44d5b71be">APP_TIMER_CONFIG_OP_QUEUE_SIZE</a>.</p> <p>I suggest you set the APP_TIMER_WITH_PROFILER config flag and monitor <a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/group__app__timer.html?cp=9_1_6_10_54_20#ga565f5b5c530dfc52c45d79c12f6615be">app_timer_op_queue_utilization_get</a>.</p> <p>You can also try to increase <a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/group__app__timer.html?cp=9_1_6_10_54_11#ga76c7bd6b9154233152895f00fe226709">APP_TIMER_SCHED_EVENT_DATA_SIZE</a><span>&nbsp;if the above solution does not work.</span></p><div style="clear:both;"></div>