Error in dwm_anchor_list_get()

Hello, ‘dwm_anchor_list_get’ fails with error “DWM1001_RV_ERR: 3”

//uart interface
hal:     UART: Tx 2 bytes: 0x0b00
lmh: rx started, timeout period changed to 18 ms
hal:     UART: Rx 3 bytes: 0x400103
lmh: *** ERROR *** HAL_UART: DWM1001_RV_ERR: 3


//SPI interface
hal:     SPI: Tx 2 bytes: 0x0b00
lmh:     SPI0: Rx step 1:
lmh:     SPI0: Wait 1 ms...
hal:     SPI: Rx 1 bytes: 0x03
lmh:     SPISPI0: Rx step 2:
lmh:     SPI0: Wait 1 ms...
hal:     SPI: Rx 3 bytes: 0x400103
lmh:     SPI0: Wait 1 ms...
lmh: *** ERROR *** HAL_SPI: DWM1001_RV_ERR: 3
Check Tx&Rx:

It is called like this:

  dwm_anchor_list_t a_list;
  int rv, err_cnt = 0, i=0;

  rv = Test_CheckTxRx(dwm_anchor_list_get(&a_list));

  if(rv == RV_OK)
  { ..... (print struct as in the API Guide) }

My node configuration, is set with ‘dwm_cfg_anchor_set’:

  cfg_an.initiator = 1;
  cfg_an.bridge = 0;
  cfg_an.common.enc_en = 0;
  cfg_an.common.led_en = 1;
  cfg_an.common.ble_en = 1;
  cfg_an.common.uwb_mode = DWM_UWB_MODE_ACTIVE;
  cfg_an.common.fw_update_en = 0;

My network is 4 anchors + 1 tag. The node’s firmware is fw2 fw_ver=x01030001 cfg_ver=x00010700
The node is connected to a Raspberry.

My idea is to log info of all visible anchors. Has anyone used this function and does it require any different anchor configuration? What is this error about?