I myself marked it as a duplicate because they are essentially the same issue on the exact same program and OS: Manual WiFi connection values will not save and both tend to make the network connection previously saved "disappear" out of sight and/or stop showing up entirely.
I myself marked it as a duplicate because they are essentially the same issue on the exact same program and OS: Manual WiFi connection values will not save and both tend to make the network connection previously saved "disappear" out of sight and/or stop showing up entirely.