Update: after re-booting the router the connection is resumed, unless that is done Ubuntu is unable to connect even after several attempts at restarting the laptop, not even using an Android (4.4.2) phone as a modem doesn't help distribute the connection.
Update: after re-booting the router the connection is resumed, unless that is done Ubuntu is unable to connect even after several attempts at restarting the laptop, not even using an Android (4.4.2) phone as a modem doesn't help distribute the connection.