From ubermix Wiki
Some connections to wireless networks that use older WEP encryption with pre-shared keys must be configured properly before they will function. If you are experiencing problems connecting to WEP a WEP encrypted network, do the following:
- Right-click on the Network Connection icon (next to the battery icon) in the top-right corner of the screen and select "Edit Connections"
- Click the "Wireless" tab in the window that appears, select your wireless network, and click "Edit"
- Click on the "Wireless Security" tab at the top, and select "Shared Key" from the "Authentication" pop-up menu
- Click "Apply" and retry connecting to the wireless network