chewitt So meanwhile I managed to get it working but I don't really know why. I connected initially a nano router in client mode to get internet access. Then I just retried to connect to the Wifi another time and it just connected. Before I am sure I used a keyboard to enter the wifi password. The time it worked I used the on screen keyboard and clicked with the mouse to enter it.
Klojum Sorry I wanted to type LibreELEC not OpenELEC. What is dmesg?