I had to select wired network when installing OSMC on my SD card and then select wifi in OSMC settings. If I used wireless when building the image it would not connect. Maybe you can try this?
I just fixed it. Just reinstall OSMC and check wired connection instead of wireless. Connect it to your router or if you have a TV just use your remote. Then connect to your WiFi and enter your password. Then you should have an internet connection.