I just changed my router wireless password, but when I go to Settings->Network->Wireless->Mynetworkname and click "Settings", nothing happens. I've also tried to "Forget network", which just disables it for a brief time before it pops back into the list of available wireless networks. When I do "sudo service network-manager restart" and "sudo systemctl restart NetworkManager", the "Wireless" window just closes and I get an error "Sorry, Ubuntu 16.04 has experienced an internal error. If you notice further problems, try restarting the computer." Restarting it does not help.
Suggestions for how to fix this would be greatly appreciated!