How to remove virtual network adapter?

Recently, I added one layer to my network(basically I've a router doing only a modem, with its own 192.168.0.x network, and then my new LAN+WIFI router having the 192.168.1.x network). Only my new router is connected to the 192.168.0.1:

I've a ubuntu server that has troubles changing its IP. It was initially set to have the 192.168.0.30 IP, but now I did set it to be 192.168.1.30.

when I run a ifconfig, it seems to be correct:

ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:7c:e2:23:1a  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.30  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::8ac5:cf7:6143:f780  prefixlen 64  scopeid 0x20<link>
        ether 78:24:af:33:78:db  txqueuelen 1000  (Ethernet)
        RX packets 189577066  bytes 154695799627 (154.6 GB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 315203982  bytes 395590619318 (395.5 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 20  memory 0xf7c00000-f7c20000

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 4440746  bytes 1244622579 (1.2 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4440746  bytes 1244622579 (1.2 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 10.8.0.1  netmask 255.255.255.0  destination 10.8.0.1
        inet6 fe80::dab:ab8c:8423:b9a  prefixlen 64  scopeid 0x20<link>
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 100  (UNSPEC)
        RX packets 14116  bytes 2820558 (2.8 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 62000  bytes 71992130 (71.9 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

But for some reason, when I try to like ping google.com, i get this:

ping google.com
PING google.com (172.217.168.46) 56(84) bytes of data.
From J4N-NAS (192.168.0.30) icmp_seq=1 Destination Host Unreachable
From J4N-NAS (192.168.0.30) icmp_seq=2 Destination Host Unreachable
From J4N-NAS (192.168.0.30) icmp_seq=3 Destination Host Unreachable
From J4N-NAS (192.168.0.30) icmp_seq=4 Destination Host Unreachable

And I did notice this on my webmin user interface: A virtual interface on 192.168.0.30. I tried to deactivate it, it fails with: SIOCSIFFLAGS: Cannot assign requested address, and I don't see it in my ifconfig.

I managed to get my ping to google working by doing a sudo ip route add default via 192.168.1.1, but I still get(after reboot) a 192.168.0.30 virtual address. How to get rid of it? What could cause it?