I had the same problem as Heiss. I needed to connect to a new wi-fi network after moving houses. Luckly, I have one of those travel routers, the GL-iNet Mango. I setup the new wi-fi network in the travel router. Then, I wired connected the travel router to the Raspberry Pi with the Volumio SD card in it. Then connected my laptop to the travel router wi-fi network and then I was able to connect to Volumio. In Volumio, I then went to Network settings, in wireless connections, selected my new home wi-fi network, input the password and saved. Restarted Volumio. Unpluged the wired travel router from the Raspberry Pi. Changed my laptop to the home wi-fi and was able to successfullly connect to Volumio.