您好，ble_gap_adv_start返回SDK_ERR_DISALLOWED的原因如下:

enum gap_state_id
{
    /// Idle state - no on going operation
    BLE_GAP_IDLE = 0,

    /// Busy state - reset device on going
    BLE_GAP_BUSY_RESET,

    /// Busy state - advertising operation on going
    BLE_GAP_BUSY_ADV,

    /// Busy state - scanning operation on going
    BLE_GAP_BUSY_SCAN,

    /// Busy state - initiating operation on going
    BLE_GAP_BUSY_INIT,

    /// Busy state - periodic sync operation on going
    BLE_GAP_BUSY_PER_SYNC,
};

if (sdk_gap_env.adv_env[adv_idx].curr_state != BLE_GAP_ACTV_STATE_IDLE) {
    error = SDK_ERR_DISALLOWED;
    break;
}
  

您这边可以排查下，是否已经在广播了；