networking reset failed

[GamerGaskin]

I have set my own ip address on my computer that I will use as a server.
enter this sudo /etc/init.d/networking restart
and then it says failed
How can I solve this?

addition
he doesn't know my network interfaces at all

because wants to log in to this pc with remmina

[rene]

/etc/init.d scripts are essentially obsolete, it's now systemctl invocations. As to the issue itself: the most trouble-free method is not using a static IP as such and in the old-fashioned sense, but configuring your DHCP-server (your router, that is) to hand out the same IP to the same system by configuring a MAC-based IP reservation through it. Still the same IP for the same system always, and no need to reconfigure on reinstall, say, as well things working the same over any distribution: you just keep DHCP enabled on the system itself.

Doubly emphasized due to this all being a bit of a mess. In essence, NetworkManager is in control of connections on Ubuntu/Mint and configuring a static IP through it is certainly possible but would imply needing e.g. autologin for the user with that specific static IP configuration set up. Retreating to lower levels we find that Ubuntu has at the time of I believe Mint 19 switched to netplan whereas Mint decided to stick with ifupdown. I'm on Mint 19 on would as such advise /etc/network/interfaces tweakage but am unsure what Mint 20 did in the netplan/ifupdown context (and would have to look up how to do it "right" if now former).

I.e., just say no and configure your router instead.