Error occurred opening serial port. (NRF_ERROR_TIMEOUT)

Question

Hi!, 
 I'm newbie with nRF52. I have a nRF51 Development Kit and a nRF52 Development Kit. 
 I have installed nRFconnect (for Ubuntu 64 bits) in Fedora 24 Workstation (64 bits) 
 nRFConnect starts well but when I select the serial port (/dev/ttyACM0 for nRF51 or /dev/ttyACM1 for nRF52) I received this error: 
 
 2016-09-20T11:05:50.744Z INFO
Application data folder:
/home/javier/.config/nrfconnect
2016-09-20T11:05:51.111Z INFO Ready.
Select serial port to connect to
adapter. 2016-09-20T11:06:01.685Z INFO
Could not load nrfjprog DLL, firmware
detection and programming will not be
available. 2016-09-20T11:06:01.686Z
INFO Opening adapter connected to
/dev/ttyACM1 2016-09-20T11:06:01.700Z
INFO Successfully opened /dev/ttyACM1.
Baud rate: 115200. Flow control: none.
Parity: none. 
 2016-09-20T11:06:01.700Z DEBUG State
change: STATE_START -> STATE_RESET 
 2016-09-20T11:06:01.701Z DEBUG 
1 -> []
type: RESERVED_5 reliable: no seq#:0 ack#:0
payload_length:0 data_integrity:0
err_code:0 2016-09-20T11:06:01.702Z
INFO Reset performed on adapter
/dev/ttyACM1 2016-09-20T11:06:02.000Z
DEBUG State change: STATE_RESET ->
STATE_UNINITIALIZED 
 2016-09-20T11:06:02.000Z DEBUG 
2 -> [01 7e ]
type: LINK_CONTROL_PACKET reliable: no
seq#:0 ack#:0 payload_length:2
data_integrity:0 err_code:0
[SYNC] 2016-09-20T11:06:02.250Z DEBUG 
3 -> [01 7e ]
type: LINK_CONTROL_PACKET reliable: no
seq#:0 ack#:0 payload_length:2
data_integrity:0 err_code:0
[SYNC] 2016-09-20T11:06:02.500Z DEBUG 
4 -> [01 7e ]
type: LINK_CONTROL_PACKET reliable: no
seq#:0 ack#:0 payload_length:2
data_integrity:0 err_code:0
[SYNC] 2016-09-20T11:06:02.751Z DEBUG 
5 -> [01 7e ]
type: LINK_CONTROL_PACKET reliable: no
seq#:0 ack#:0 payload_length:2
data_integrity:0 err_code:0
[SYNC] 2016-09-20T11:06:03.001Z DEBUG State
change: STATE_UNINITIALIZED ->
STATE_FAILED 
 2016-09-20T11:06:03.700Z ERROR Error
occurred opening serial port.
(NRF_ERROR_TIMEOUT)
2016-09-20T11:06:03.858Z DEBUG Error:
Error occurred opening serial port.
(NRF_ERROR_TIMEOUT)
at Adapter. (/home/javier/Descargas/nrf-connect-linux-x64/resources/app/js/actions/adapterActions.js:151:34)
at emitOne (events.js:77:13)
at Adapter.emit (events.js:169:7)
at Adapter._emitError (/home/javier/Descargas/nrf-connect-linux-x64/resources/app/node_modules/pc-ble-driver-js/api/adapter.js:176:14)
at Adapter._checkAndPropagateError (/home/javier/Descargas/nrf-connect-linux-x64/resources/app/node_modules/pc-ble-driver-js/api/adapter.js:166:18)
at _adapter.open.err (/home/javier/Descargas/nrf-connect-linux-x64/resources/app/node_modules/pc-ble-driver-js/api/adapter.js:266:22) 
 
 As I can solve it? 
 Best regards