After installing Ubuntu again, I noticed a problem, and the problem is that the Applet Device Manager displays an empty Wi-Fi tag. If I'm connecting to the Internet (by LAN), and when I click the right method, most options are inactive and below the Ethernet Network Device not managed! (Attached Pictures) I now imported my openvpn connection but I can not connect to it.
I also made these changes:
First it was
[main] plugins=ifupdown,keyfile [ifupdown] managed=false [device] wifi.scan-rand-mac-address=no
And I changed ifdown to this
[ifupdown] managed = true
but problem not solve
Similarly, I can not connect to the VPN network, and I feel that these two problems are quite interrelated!