Yeah, this topic again. Wifi does not work on new installs of the latest version of Pi2/3 OSMC. You can select the right SSID, but the password always fails. Trying to manually connect causes the above 'Unhandled Exception error.
I’ve followed the previous threads and installed OSMC_TGT_rbp2_20220314.img.gz, to make it work. You’re then having to update from there. (Big thank you to DarwinDesign for this post.)
It works, but it’s a needless workaround.